diff --git a/TODO.md b/TODO.md
index d389f7d..b4a3de5 100644
--- a/TODO.md
+++ b/TODO.md
@@ -47,7 +47,9 @@ Implementation does not mean a feature has been tested on every headset.
 - [x] Resume a movie or episode from its saved position.
 - [x] Start a partially watched title from the beginning.
 - [x] Report playback start, progress, pause state, and stop events to Jellyfin.
-- [ ] Manually mark a movie, episode, season, or series as watched or unwatched.
+- [x] Manually mark a movie or episode as watched or unwatched.
+- [x] Manually mark a season as watched or unwatched.
+- [x] Manually mark a series as watched or unwatched.
 - [x] Select between multiple media versions
 - [ ] Browse and play trailers and extras.
 
diff --git a/scripts/jellyfin/client.gd b/scripts/jellyfin/client.gd
index c8a4ae6..8724170 100644
--- a/scripts/jellyfin/client.gd
+++ b/scripts/jellyfin/client.gd
@@ -133,6 +133,9 @@ func resume_items() -> Dictionary:
 func details(id: String) -> Dictionary:
 	return await request("/Users/%s/Items/%s" % [user_id, id.uri_encode()])
 
+func set_watched(id: String, watched: bool) -> Dictionary:
+	return await request("/Users/%s/PlayedItems/%s" % [user_id.uri_encode(), id.uri_encode()], HTTPClient.METHOD_POST if watched else HTTPClient.METHOD_DELETE)
+
 func seasons(series_id: String) -> Dictionary:
 	return await request("/Shows/%s/Seasons" % series_id.uri_encode() + query({"UserId": user_id, "Fields": "Overview,UserData", "EnableUserData": "true"}))
 
diff --git a/scripts/ui/details.gd b/scripts/ui/details.gd
index 45242da..139b0e4 100644
--- a/scripts/ui/details.gd
+++ b/scripts/ui/details.gd
@@ -16,6 +16,8 @@ var series_browser: SeriesBrowser
 var play_button: Button
 var play_from_start_button: Button
 var version_button: Button
+var watched_control: VBoxContainer
+var resume_label: Label
 var back_button: Button
 var title_label: Label
 var overview_label: Label
@@ -30,8 +32,10 @@ func _ready() -> void:
 		artwork.api = api
 		add_child(artwork)
 	var navigation := HBoxContainer.new()
+	navigation.add_theme_constant_override("separation", 12)
 	add_child(navigation)
 	back_button = Widgets.button("Back to library", func(): back_requested.emit(), navigation)
+	back_button.size_flags_vertical = Control.SIZE_SHRINK_BEGIN
 	scroll = ScrollContainer.new()
 	scroll.size_flags_vertical = Control.SIZE_EXPAND_FILL
 	scroll.horizontal_scroll_mode = ScrollContainer.SCROLL_MODE_DISABLED
@@ -48,6 +52,8 @@ func _ready() -> void:
 		series_browser.api = api
 		series_browser.artwork = artwork
 		series_browser.series_id = str(item.Id)
+		series_browser.series_item = item
+		series_browser.navigation_host = navigation
 		series_browser.selected_season = initial_season
 		series_browser.play_requested.connect(func(episode: Dictionary): play_requested.emit(episode))
 		series_browser.version_requested.connect(func(episode: Dictionary): version_requested.emit(episode))
@@ -135,11 +141,31 @@ func _build_playback(parent: VBoxContainer) -> void:
 	if position > 0:
 		play_from_start_button = Widgets.button("Play from start", func(): play_from_start_requested.emit(item), actions)
 		play_from_start_button.custom_minimum_size = Vector2(200, 64)
-		_muted("Continue from " + DetailsMetadata.duration(position), parent, 20)
+		resume_label = _muted("Continue from " + DetailsMetadata.duration(position), parent, 20)
+	var secondary_actions := HFlowContainer.new()
+	secondary_actions.add_theme_constant_override("h_separation", 12)
+	secondary_actions.add_theme_constant_override("v_separation", 12)
+	parent.add_child(secondary_actions)
+	if item.get("Type", "") in ["Movie", "Episode"]:
+		watched_control = preload("res://scripts/ui/watched_control.gd").new()
+		watched_control.api = api
+		watched_control.item = item
+		watched_control.changed.connect(_refresh_playback_state)
+		secondary_actions.add_child(watched_control)
+		watched_control.button.custom_minimum_size.y = 64
 	var sources: Array = item.get("MediaSources", []) if item.get("MediaSources") else []
 	if sources.size() > 1:
-		version_button = Widgets.button("Choose version", func(): version_requested.emit(item), actions)
+		version_button = Widgets.button("Choose version", func(): version_requested.emit(item), secondary_actions)
 		version_button.custom_minimum_size = Vector2(200, 64)
+		version_button.size_flags_vertical = Control.SIZE_SHRINK_BEGIN
+
+func _refresh_playback_state() -> void:
+	var position := int(item.UserData.get("PlaybackPositionTicks", 0))
+	play_button.text = "Resume" if position > 0 else ("Play episode" if item.get("Type") == "Episode" else "Play movie")
+	if is_instance_valid(play_from_start_button): play_from_start_button.visible = position > 0
+	if is_instance_valid(resume_label):
+		resume_label.visible = position > 0
+		resume_label.text = "Continue from " + DetailsMetadata.duration(position)
 
 func _build_information() -> void:
 	var section := VBoxContainer.new()
diff --git a/scripts/ui/episode_card.gd b/scripts/ui/episode_card.gd
index 0293f8b..ff8ef72 100644
--- a/scripts/ui/episode_card.gd
+++ b/scripts/ui/episode_card.gd
@@ -6,6 +6,10 @@ signal version_requested(item: Dictionary)
 
 var item: Dictionary
 var artwork: ArtworkLoader
+var api: JellyfinClient
+var watched_control: VBoxContainer
+var watched_badge: Control
+var facts_label: Label
 var play_button: Button
 var version_button: Button
 var thumbnail: TextureRect
@@ -44,12 +48,12 @@ func _ready() -> void:
 	title_label = _label(DetailsMetadata.title(item, "Episode"), text, 26)
 	var facts := DetailsMetadata.facts(item)
 	var user: Dictionary = item.get("UserData", {}) if item.get("UserData") else {}
-	if user.get("Played", false):
-		Widgets.watched_badge(frame)
+	watched_badge = Widgets.watched_badge(frame)
+	watched_badge.visible = user.get("Played", false)
 	var position := int(user.get("PlaybackPositionTicks", 0))
 	if position > 0: facts.append("Continue from " + DetailsMetadata.duration(position))
-	if not facts.is_empty():
-		_label("  /  ".join(facts), text, 20).add_theme_color_override("font_color", Color("b0bbce"))
+	facts_label = _label("  /  ".join(facts), text, 20)
+	facts_label.add_theme_color_override("font_color", Color("b0bbce"))
 	_label(str(item.get("Overview") if item.get("Overview") else "No description available."), text, 22)
 	play_button = Widgets.button("Resume episode" if position > 0 else "Play episode", func(): chosen.emit(item), image_column)
 	play_button.custom_minimum_size = Vector2(190, 56)
@@ -60,6 +64,21 @@ func _ready() -> void:
 	if sources.size() > 1:
 		version_button = Widgets.button("Choose version", func(): version_requested.emit(item), image_column)
 		version_button.accessibility_name = "Choose version of " + title_label.text
+	watched_control = preload("res://scripts/ui/watched_control.gd").new()
+	watched_control.api = api
+	watched_control.item = item
+	watched_control.changed.connect(_refresh_user_data)
+	text.add_child(watched_control)
+
+func _refresh_user_data() -> void:
+	var user: Dictionary = item.UserData
+	var position := int(user.get("PlaybackPositionTicks", 0))
+	var facts := DetailsMetadata.facts(item)
+	if position > 0: facts.append("Continue from " + DetailsMetadata.duration(position))
+	facts_label.text = "  /  ".join(facts)
+	watched_badge.visible = user.get("Played", false)
+	play_button.text = "Resume episode" if position > 0 else "Play episode"
+	play_button.accessibility_name = play_button.text + " " + title_label.text + (", watched" if user.get("Played", false) else "")
 
 func _label(value: String, parent: Node, font_size: int) -> Label:
 	var label := Widgets.label(value, parent, font_size)
diff --git a/scripts/ui/series_browser.gd b/scripts/ui/series_browser.gd
index dacfed3..7ab0528 100644
--- a/scripts/ui/series_browser.gd
+++ b/scripts/ui/series_browser.gd
@@ -8,6 +8,7 @@ signal section_changed
 var api: JellyfinClient
 var artwork: ArtworkLoader
 var series_id := ""
+var series_item: Dictionary = {}
 var season_grid: HFlowContainer
 var season_section: VBoxContainer
 var episode_section: VBoxContainer
@@ -17,6 +18,10 @@ var season_description: Label
 var all_seasons_button: Button
 var generation := 0
 var selected_season: Dictionary = {}
+var navigation_host: HBoxContainer
+var navigation: HBoxContainer
+var watched_host: VBoxContainer
+var watched_control: VBoxContainer
 
 func _ready() -> void:
 	add_theme_constant_override("separation", 20)
@@ -31,9 +36,18 @@ func _ready() -> void:
 	episode_section = VBoxContainer.new()
 	episode_section.add_theme_constant_override("separation", 18)
 	add_child(episode_section)
-	var navigation := HBoxContainer.new()
-	episode_section.add_child(navigation)
+	navigation = HBoxContainer.new()
+	navigation.size_flags_horizontal = Control.SIZE_EXPAND_FILL
+	navigation.add_theme_constant_override("separation", 12)
+	(navigation_host if navigation_host != null else self).add_child(navigation)
 	all_seasons_button = Widgets.button("All seasons", _show_seasons, navigation)
+	all_seasons_button.size_flags_vertical = Control.SIZE_SHRINK_BEGIN
+	var spacer := Control.new()
+	spacer.size_flags_horizontal = Control.SIZE_EXPAND_FILL
+	navigation.add_child(spacer)
+	watched_host = VBoxContainer.new()
+	navigation.add_child(watched_host)
+	navigation.hide()
 	episode_heading = _label("", episode_section, 28)
 	season_description = _label("", episode_section, 22)
 	episode_list = VBoxContainer.new()
@@ -46,6 +60,9 @@ func _ready() -> void:
 func load_seasons() -> void:
 	generation += 1
 	var current := generation
+	if series_item.is_empty(): series_item = {"Id": series_id, "Type": "Series"}
+	all_seasons_button.hide()
+	_set_watched_control(series_item, _series_watched_changed.bind(current), "Applies to every episode in every season of this series.")
 	_clear(season_grid)
 	_label("Loading seasons...", season_grid, 22)
 	var result := await api.seasons(series_id)
@@ -56,6 +73,15 @@ func load_seasons() -> void:
 		Widgets.button("Retry seasons", load_seasons, season_grid)
 		return
 	var seasons: Array = result.data.get("Items", [])
+	var all_watched := not seasons.is_empty()
+	for season in seasons:
+		var user: Dictionary = season.get("UserData", {}) if season.get("UserData") else {}
+		all_watched = all_watched and bool(user.get("Played", false))
+	var series_user: Dictionary = series_item.get("UserData", {}) if series_item.get("UserData") else {}
+	series_user["Played"] = all_watched
+	series_item["UserData"] = series_user
+	watched_control._refresh()
+	watched_control.button.disabled = seasons.is_empty()
 	if seasons.is_empty():
 		_label("No seasons available.", season_grid, 22)
 	for season in seasons:
@@ -71,6 +97,8 @@ func open_season(season: Dictionary) -> void:
 	var current := generation
 	season_section.hide()
 	episode_section.show()
+	all_seasons_button.show()
+	_set_watched_control(selected_season, _season_watched_changed.bind(current), "Applies to every episode in this season.")
 	all_seasons_button.grab_focus()
 	episode_heading.text = str(season.get("Name", "Season")) + " episodes"
 	season_description.text = str(season.get("Overview") if season.get("Overview") else "")
@@ -102,18 +130,57 @@ func open_season(season: Dictionary) -> void:
 		if card.item.get("ParentIndexNumber") == null:
 			card.item["ParentIndexNumber"] = season.get("IndexNumber")
 		card.artwork = artwork
+		card.api = api
 		card.chosen.connect(func(chosen: Dictionary): play_requested.emit(chosen))
 		card.version_requested.connect(func(chosen: Dictionary): version_requested.emit(chosen))
 		episode_list.add_child(card)
+		card.watched_control.changed.connect(_refresh_season_watched)
+	_refresh_season_watched()
 	section_changed.emit()
 
+func _refresh_season_watched() -> void:
+	if watched_control.busy: return
+	var all_watched := true
+	var count := 0
+	for card in episode_list.get_children():
+		if not card is EpisodeCard: continue
+		count += 1
+		var user: Dictionary = card.item.get("UserData", {}) if card.item.get("UserData") else {}
+		all_watched = all_watched and bool(user.get("Played", false))
+	selected_season["UserData"] = {"Played": all_watched and count > 0}
+	watched_control._refresh()
+	watched_control.button.disabled = count == 0
+
+func _set_watched_control(item: Dictionary, action: Callable, tooltip: String) -> void:
+	navigation.show()
+	_clear(watched_host)
+	watched_control = preload("res://scripts/ui/watched_control.gd").new()
+	watched_control.api = api
+	watched_control.item = item
+	watched_control.changed.connect(action)
+	watched_host.add_child(watched_control)
+	watched_control.button.disabled = true
+	watched_control.button.tooltip_text = tooltip
+
+func _series_watched_changed(current: int) -> void:
+	if not _current(current): return
+	await load_seasons()
+	if _current(current + 1): watched_control.button.grab_focus()
+
+func _season_watched_changed(current: int) -> void:
+	if not _current(current): return
+	await open_season(selected_season)
+	if _current(current + 1) and not selected_season.is_empty():
+		watched_control.button.grab_focus()
+
 func _show_seasons() -> void:
 	selected_season = {}
 	generation += 1
 	episode_section.hide()
+	navigation.hide()
 	season_section.show()
 	section_changed.emit()
-	if season_grid.get_child_count() == 0: load_seasons()
+	load_seasons()
 	if season_grid.get_child_count() > 0:
 		var first := season_grid.get_child(0) as Control
 		if first and first.focus_mode != Control.FOCUS_NONE: first.grab_focus()
diff --git a/scripts/ui/watched_control.gd b/scripts/ui/watched_control.gd
new file mode 100644
index 0000000..f232f7c
--- /dev/null
+++ b/scripts/ui/watched_control.gd
@@ -0,0 +1,47 @@
+extends VBoxContainer
+
+signal changed
+
+var api: JellyfinClient
+var item: Dictionary
+var button: Button
+var status: Label
+var busy := false
+
+func _ready() -> void:
+	button = Widgets.button("", _toggle, self)
+	button.size_flags_horizontal = Control.SIZE_SHRINK_BEGIN
+	status = Widgets.label("", self, 18)
+	status.autowrap_mode = TextServer.AUTOWRAP_WORD_SMART
+	status.custom_minimum_size.x = 200
+	status.hide()
+	_refresh()
+
+func _refresh() -> void:
+	var user: Dictionary = item.get("UserData", {}) if item.get("UserData") else {}
+	button.text = "Mark as unwatched" if user.get("Played", false) else "Mark as watched"
+	button.accessibility_name = button.text + " " + DetailsMetadata.title(item)
+
+func _toggle() -> void:
+	if busy: return
+	busy = true
+	button.disabled = true
+	status.text = "Saving..."
+	status.show()
+	var user: Dictionary = item.get("UserData", {}) if item.get("UserData") else {}
+	var result := await api.set_watched(str(item.Id), not user.get("Played", false))
+	if not is_inside_tree(): return
+	busy = false
+	button.disabled = false
+	if not result.ok:
+		status.text = result.error
+		return
+	if not result.data is Dictionary or not result.data.get("Played") is bool:
+		status.text = "Could not confirm watched status. Reopen the item to refresh it."
+		return
+	var updated := user.duplicate(true)
+	updated.merge(result.data, true)
+	item["UserData"] = updated
+	status.hide()
+	_refresh()
+	changed.emit()
diff --git a/scripts/ui/widgets.gd b/scripts/ui/widgets.gd
index 3fd6eac..f1ba847 100644
--- a/scripts/ui/widgets.gd
+++ b/scripts/ui/widgets.gd
@@ -26,7 +26,7 @@ static func input(placeholder: String, parent: Node, secret: bool = false) -> Li
 	parent.add_child(result)
 	return result
 
-static func watched_badge(image_frame: PanelContainer) -> void:
+static func watched_badge(image_frame: PanelContainer) -> Control:
 	var overlay := Control.new()
 	overlay.mouse_filter = Control.MOUSE_FILTER_IGNORE
 	image_frame.add_child(overlay)
@@ -41,6 +41,7 @@ static func watched_badge(image_frame: PanelContainer) -> void:
 	badge.offset_top = 8
 	badge.offset_right = -8
 	badge.offset_bottom = 36
+	return overlay
 
 static func theme() -> Theme:
 	var result := Theme.new()
diff --git a/tests/test_http.gd b/tests/test_http.gd
index 228b1f5..61313c8 100644
--- a/tests/test_http.gd
+++ b/tests/test_http.gd
@@ -64,6 +64,13 @@ func run_checks() -> void:
 	await api.episodes("show id", "season & id", 100)
 	check("SeasonId=season%20%26%20id" in last_request and "StartIndex=100" in last_request, "Episode pagination stays inside the selected season")
 	check("Fields=Overview%2CUserData%2CMediaSources" in last_request and "IsMissing=false" in last_request, "Episode cards request versions and summaries and exclude missing episodes")
+	payload = '{"Played":true,"PlaybackPositionTicks":0}'
+	code = 200
+	result = await api.set_watched("movie id", true)
+	check(result.ok and result.data.Played and last_request.begins_with("POST /jellyfin/Users/fixture-user/PlayedItems/movie%20id "), "Mark watched sends an authenticated POST for the selected item")
+	payload = '{"Played":false,"PlaybackPositionTicks":0}'
+	result = await api.set_watched("episode id", false)
+	check(result.ok and not result.data.Played and last_request.begins_with("DELETE /jellyfin/Users/fixture-user/PlayedItems/episode%20id "), "Mark unwatched sends DELETE and returns updated user data")
 	code = 401
 	payload = ""
 	result = await api.request("/Users/Me")
diff --git a/tests/test_series.gd b/tests/test_series.gd
index e37b01b..13456b8 100644
--- a/tests/test_series.gd
+++ b/tests/test_series.gd
@@ -6,11 +6,28 @@ class FixtureApi extends JellyfinClient:
 	var fail_episodes := false
 	var empty_seasons := false
 	var empty_episodes := false
+	var watched_states: Dictionary = {}
+	var watched_calls: Array = []
+	var fail_watched := false
+	var hold_watched := false
+	signal release_watched
+
+	func set_watched(id: String, watched: bool) -> Dictionary:
+		watched_calls.append([id, watched])
+		if hold_watched: await release_watched
+		await get_tree().process_frame
+		if fail_watched: return {"ok": false, "error": "Offline"}
+		watched_states[id] = watched
+		if id == "agatha":
+			for season in season_items: watched_states[season.Id] = watched
+		return {"ok": true, "data": {"Played": watched}}
 	var season_items := [{"Id": "one", "Name": "Season 1", "IndexNumber": 1}, {"Id": "two", "Name": "Season 2", "IndexNumber": 2}]
 
 	func seasons(_series_id: String) -> Dictionary:
 		await get_tree().process_frame
 		if fail_seasons: return {"ok": false, "error": "Offline"}
+		for season in season_items:
+			season["UserData"] = {"Played": watched_states.get(season.Id, false)}
 		return {"ok": true, "data": {"Items": [] if empty_seasons else season_items}}
 
 	func episodes(series_id: String, season_id: String, offset: int = 0) -> Dictionary:
@@ -24,6 +41,9 @@ class FixtureApi extends JellyfinClient:
 				items.append({"Id": season_id + str(index), "Name": ["Seekest Thou the Road", "Circle Sewn with Fate", "Through the trials", "The final chapter"][index], "IndexNumber": index + 1, "RunTimeTicks": 24000000000, "CommunityRating": 7.0, "Overview": "Agatha and her companions face another trial on the Witches' Road.", "UserData": {"PlaybackPositionTicks": 3000000000 if index == 0 else 0, "Played": index == 1}})
 		if offset == 0 and not items.is_empty():
 			items[0]["MediaSources"] = [{"Id": "first"}, {"Id": "second"}]
+		if watched_states.has(season_id):
+			for item in items:
+				item.UserData = {"Played": watched_states[season_id], "PlaybackPositionTicks": 0}
 		return {"ok": true, "data": {"Items": items, "TotalRecordCount": 0 if empty_episodes else 4}}
 
 var failures := 0
@@ -87,7 +107,34 @@ func run_checks() -> void:
 		await settle()
 		check(first.size.x <= view.scroll.size.x, "Episode cards must fit the available panel width.")
 		check(first.title_label.get_global_rect().end.x <= view.scroll.get_global_rect().end.x, "Episode text must remain inside the panel.")
+		check(is_equal_approx(view.back_button.global_position.y, browser.all_seasons_button.global_position.y) and is_equal_approx(view.back_button.global_position.y, browser.watched_control.button.global_position.y), "All three season navigation buttons share one row.")
+		check(browser.watched_control.get_global_rect().end.x <= view.get_global_rect().end.x, "The season watched action fits the right edge.")
 	root.size.x = 1536
+	check(browser.watched_control.button.text == "Mark as watched", "Partly watched seasons offer Mark as watched.")
+	browser.watched_control.button.pressed.emit()
+	await settle()
+	check(api.watched_calls == [["one", true]], "The season action sends the season ID rather than an episode or series ID.")
+	check(browser.watched_control.button.text == "Mark as unwatched", "Watched seasons offer Mark as unwatched.")
+	for card in browser.episode_list.get_children():
+		check(card.watched_badge.visible and card.play_button.text == "Play episode", "All episode pages refresh their badges and progress after a season change.")
+	browser.watched_control.button.pressed.emit()
+	await settle()
+	for card in browser.episode_list.get_children():
+		check(not card.watched_badge.visible, "Marking a season unwatched refreshes every episode.")
+	api.fail_watched = true
+	browser.watched_control.button.pressed.emit()
+	await settle()
+	check(browser.watched_control.status.visible and not browser.watched_control.button.disabled, "A failed season change shows an error and permits retry.")
+	check(not browser.episode_list.get_child(0).watched_badge.visible, "Failed season changes preserve episode state.")
+	api.fail_watched = false
+	api.hold_watched = true
+	browser.watched_control.button.pressed.emit()
+	browser.open_season(api.season_items[1])
+	await settle()
+	api.release_watched.emit()
+	await settle()
+	check(browser.selected_season.Id == "two" and browser.episode_list.get_child(0).item.Id == "two0", "A late season update cannot replace another season's view.")
+	api.hold_watched = false
 	browser.open_season(api.season_items[0])
 	browser.all_seasons_button.pressed.emit()
 	browser.open_season(api.season_items[1])
@@ -115,6 +162,41 @@ func run_checks() -> void:
 	browser.season_grid.get_child(1).pressed.emit()
 	await settle()
 	check(browser.season_grid.get_child_count() == 2, "Retry must restore season selection.")
+	api.empty_episodes = false
+	check(browser.watched_control.item.Id == "agatha" and not browser.all_seasons_button.visible, "The overview offers a series action without All seasons.")
+	browser.watched_control.button.pressed.emit()
+	await settle()
+	check(api.watched_calls.back() == ["agatha", true], "The overview submits the series ID for a whole-series update.")
+	check(browser.watched_control.button.text == "Mark as unwatched", "A watched series offers Mark as unwatched.")
+	for card in browser.season_grid.get_children():
+		check(card.item.UserData.Played, "The series action refreshes every season.")
+	await capture("res://dist/series-watched-preview.png")
+	browser.open_season(api.season_items[1])
+	await settle()
+	for card in browser.episode_list.get_children():
+		check(card.watched_badge.visible, "Episodes in another season reflect the whole-series update.")
+	browser.all_seasons_button.pressed.emit()
+	await settle()
+	api.fail_watched = true
+	browser.watched_control.button.pressed.emit()
+	await settle()
+	check(browser.watched_control.status.visible and browser.watched_control.button.text == "Mark as unwatched", "A failed series change preserves state and shows an error.")
+	api.fail_watched = false
+	browser.watched_control.button.pressed.emit()
+	await settle()
+	check(api.watched_calls.back() == ["agatha", false] and browser.watched_control.button.text == "Mark as watched", "A whole series can be marked unwatched.")
+	for card in browser.season_grid.get_children():
+		check(not card.item.UserData.Played, "All seasons refresh to unwatched.")
+	api.hold_watched = true
+	browser.watched_control.button.pressed.emit()
+	browser.open_season(api.season_items[0])
+	await settle()
+	api.release_watched.emit()
+	await settle()
+	check(browser.selected_season.Id == "one" and browser.watched_control.item.Id == "one", "A late series response cannot replace the season action.")
+	api.hold_watched = false
+	browser.all_seasons_button.pressed.emit()
+	await settle()
 	api.empty_seasons = true
 	browser.load_seasons()
 	await settle()
diff --git a/tests/test_watched.gd b/tests/test_watched.gd
new file mode 100644
index 0000000..7f09d88
--- /dev/null
+++ b/tests/test_watched.gd
@@ -0,0 +1,77 @@
+extends SceneTree
+
+class FixtureApi extends JellyfinClient:
+	var calls: Array = []
+	var fail := false
+	var malformed := false
+
+	func set_watched(id: String, watched: bool) -> Dictionary:
+		calls.append([id, watched])
+		await get_tree().process_frame
+		if fail: return {"ok": false, "error": "Cannot reach the server."}
+		return {"ok": true, "data": {} if malformed else {"Played": watched, "PlaybackPositionTicks": 0, "PlayCount": 1 if watched else 0}}
+
+var failures := 0
+
+func _initialize() -> void:
+	call_deferred("run_checks")
+
+func check(condition: bool, message: String) -> void:
+	if not condition:
+		failures += 1
+		push_error(message)
+
+func settle() -> void:
+	for frame in range(5): await process_frame
+
+func run_checks() -> void:
+	var api := FixtureApi.new()
+	root.add_child(api)
+	var view := DetailsView.new()
+	view.api = api
+	view.item = {"Id": "movie", "Type": "Movie", "Name": "Example", "UserData": {"Played": false, "PlaybackPositionTicks": 7200000000, "IsFavorite": true}}
+	root.add_child(view)
+	await settle()
+	var control = view.watched_control
+	check(control.button.text == "Mark as watched", "Unwatched movies offer Mark as watched")
+	control.button.pressed.emit()
+	control.button.pressed.emit()
+	check(control.button.disabled and api.calls.size() == 1, "Saving prevents duplicate requests")
+	check(not view.item.UserData.Played, "Watched status waits for server confirmation")
+	await settle()
+	check(view.item.UserData.Played and view.item.UserData.IsFavorite, "Confirmed user data preserves unrelated fields")
+	check(control.button.text == "Mark as unwatched" and view.play_button.text == "Play movie", "Movie buttons reflect the confirmed watched state and cleared resume position")
+	check(not view.resume_label.visible and not view.play_from_start_button.visible, "Cleared progress hides stale resume controls")
+	control.button.pressed.emit()
+	await settle()
+	check(not view.item.UserData.Played and api.calls.back() == ["movie", false], "Movies can be marked unwatched again")
+	api.fail = true
+	control.button.pressed.emit()
+	await settle()
+	check(not view.item.UserData.Played and not control.button.disabled and control.status.visible, "Failed requests preserve state and allow retry")
+	api.fail = false
+	api.malformed = true
+	control.button.pressed.emit()
+	await settle()
+	check(not view.item.UserData.Played and control.status.visible, "Incomplete responses do not claim a saved change")
+	api.malformed = false
+	var episode := EpisodeCard.new()
+	episode.api = api
+	episode.artwork = view.artwork
+	episode.item = {"Id": "episode", "Type": "Episode", "Name": "Episode", "UserData": {"Played": true, "PlaybackPositionTicks": 7200000000}}
+	root.add_child(episode)
+	await settle()
+	check(episode.watched_badge.visible, "Watched episodes show a badge")
+	episode.watched_control.button.pressed.emit()
+	await settle()
+	check(not episode.watched_badge.visible and episode.play_button.text == "Play episode", "Marking an episode unwatched updates its badge and playback action")
+	check(not "Continue from" in episode.facts_label.text and not "watched" in episode.play_button.accessibility_name, "Episode progress and accessibility labels are refreshed")
+	episode.watched_control.button.pressed.emit()
+	await settle()
+	check(episode.watched_badge.visible and api.calls.back() == ["episode", true], "Episodes can be marked watched again")
+	view.queue_free()
+	episode.queue_free()
+	api.queue_free()
+	await process_frame
+	print("Watched status checks: ", "PASS" if failures == 0 else str(failures) + " failures")
+	quit(1 if failures else 0)