diff --git a/SVSim.EmulatedEntrypoint/Services/StoryService.cs b/SVSim.EmulatedEntrypoint/Services/StoryService.cs
index 82dbac6..e2c2059 100644
--- a/SVSim.EmulatedEntrypoint/Services/StoryService.cs
+++ b/SVSim.EmulatedEntrypoint/Services/StoryService.cs
@@ -192,6 +192,17 @@ public class StoryService : IStoryService
         var allProgress = await _viewer.GetProgressForChaptersAsync(
             viewerId, allChapters.Select(c => c.StoryId));
 
+        // Tutorial section (id=0) has no chapter rows server-side — the prologue is hardcoded
+        // client-side in Wizard/Prologue.cs. Derive its is_finished from viewer.tutorial_step
+        // instead (matches prod traffic_prod_626_story.ndjson btn_story_tutorial). The client
+        // uses is_finished to flip IsTutorialReplay, which is what re-enables chapter switching
+        // in AreaSelectUI.OnTouchChapterListTutorial when the user re-visits the prologue.
+        const int TutorialEndStep = 100;
+        var tutorialState = await _db.Viewers
+            .Where(v => v.Id == viewerId)
+            .Select(v => v.MissionData.TutorialState)
+            .FirstOrDefaultAsync();
+
         // Index chapters by (sectionId, charaId) for O(1) lookup in the rollup loop.
         var chaptersBySectionChara = allChapters
             .GroupBy(c => (c.SectionId, c.CharaId))
@@ -253,6 +264,8 @@ public class StoryService : IStoryService
                     }
                 }
 
+                if (s.Id == 0) sectionFinished = tutorialState >= TutorialEndStep;
+
                 if (!sectionFinished) worldComplete = false;
                 worldDto.SectionList.Add(new SectionEntry
                 {
diff --git a/SVSim.UnitTests/Story/StoryServiceTests.cs b/SVSim.UnitTests/Story/StoryServiceTests.cs
index e759b40..4bdefc9 100644
--- a/SVSim.UnitTests/Story/StoryServiceTests.cs
+++ b/SVSim.UnitTests/Story/StoryServiceTests.cs
@@ -335,6 +335,78 @@ public class StoryServiceTests
         Assert.That(section.SpoilerMessage, Is.EqualTo("story_section_14"));
     }
 
+    [Test]
+    public async Task GetSectionsAsync_tutorial_section_is_finished_when_viewer_tutorial_state_at_end_step()
+    {
+        // The tutorial section (id=0) has zero chapter rows — the prologue is hardcoded
+        // client-side in Wizard/Prologue.cs. Prod nonetheless returns is_finished=true once
+        // viewer.tutorial_step reaches 100; the client uses that to flip IsTutorialReplay,
+        // which is what re-enables chapter switching in AreaSelectUI.OnTouchChapterListTutorial.
+        // Verified against traffic_prod_626_story.ndjson btn_story_tutorial entry.
+        const long viewerId = 7L;
+        var service = NewServiceWithSeededViewerTutorialState(
+            nameof(GetSectionsAsync_tutorial_section_is_finished_when_viewer_tutorial_state_at_end_step),
+            viewerId, tutorialState: 100);
+
+        _master.Setup(m => m.GetSectionsByFamilyAsync(StoryApiType.Main))
+               .ReturnsAsync(new List<StorySection> {
+                   new() { Id = 0, WorldId = 1, StoryApiType = StoryApiType.Main, IsLeaderSelect = false } });
+        _master.Setup(m => m.GetWorldsForSectionsAsync(It.IsAny<IEnumerable<int>>()))
+               .ReturnsAsync(new List<StoryWorld> { new() { Id = 1, TitleTextKey = "world_1" } });
+        _master.Setup(m => m.GetChaptersBySectionsAsync(It.IsAny<IEnumerable<int>>()))
+               .ReturnsAsync(new List<StoryChapter>());
+        _viewer.Setup(v => v.GetProgressForChaptersAsync(viewerId, It.IsAny<IEnumerable<int>>()))
+               .ReturnsAsync(new Dictionary<int, ViewerStoryProgress>());
+
+        var resp = await service.GetSectionsAsync(StoryApiType.Main, viewerId);
+
+        var section = resp.WorldList["1"].SectionList.Single(s => s.SectionId == "0");
+        Assert.That(section.IsFinished, Is.True);
+    }
+
+    [Test]
+    public async Task GetSectionsAsync_tutorial_section_not_finished_when_viewer_mid_tutorial()
+    {
+        // Mid-tutorial (step < 100): client still needs IsTutorialReplay=false so the AreaSelectUI
+        // confirm-only-current-step flow runs. is_finished must stay false.
+        const long viewerId = 7L;
+        var service = NewServiceWithSeededViewerTutorialState(
+            nameof(GetSectionsAsync_tutorial_section_not_finished_when_viewer_mid_tutorial),
+            viewerId, tutorialState: 41);
+
+        _master.Setup(m => m.GetSectionsByFamilyAsync(StoryApiType.Main))
+               .ReturnsAsync(new List<StorySection> {
+                   new() { Id = 0, WorldId = 1, StoryApiType = StoryApiType.Main, IsLeaderSelect = false } });
+        _master.Setup(m => m.GetWorldsForSectionsAsync(It.IsAny<IEnumerable<int>>()))
+               .ReturnsAsync(new List<StoryWorld> { new() { Id = 1, TitleTextKey = "world_1" } });
+        _master.Setup(m => m.GetChaptersBySectionsAsync(It.IsAny<IEnumerable<int>>()))
+               .ReturnsAsync(new List<StoryChapter>());
+        _viewer.Setup(v => v.GetProgressForChaptersAsync(viewerId, It.IsAny<IEnumerable<int>>()))
+               .ReturnsAsync(new Dictionary<int, ViewerStoryProgress>());
+
+        var resp = await service.GetSectionsAsync(StoryApiType.Main, viewerId);
+
+        var section = resp.WorldList["1"].SectionList.Single(s => s.SectionId == "0");
+        Assert.That(section.IsFinished, Is.False);
+    }
+
+    private StoryService NewServiceWithSeededViewerTutorialState(string dbName, long viewerId, int tutorialState)
+    {
+        var db = StoryServiceTestHelpers.NewInMemoryDb(dbName);
+        db.Viewers.Add(new SVSim.Database.Models.Viewer {
+            Id = viewerId,
+            MissionData = new SVSim.Database.Models.ViewerMissionData { TutorialState = tutorialState },
+        });
+        db.SaveChanges();
+        return new StoryService(
+            _master.Object, _viewer.Object,
+            rewards: new RewardGrantService(db, NullLogger<RewardGrantService>.Instance),
+            db: db,
+            configService: StoryServiceTestHelpers.NewConfigService(),
+            deckRepository: new Mock<SVSim.Database.Repositories.Deck.IDeckRepository>().Object,
+            logger: NullLogger<StoryService>.Instance);
+    }
+
     [Test]
     public async Task GetLeaderSelectAsync_section_with_custom_leaders_returns_only_those_charas_in_min_story_id_order()
     {