diff --git a/SVSim.Bootstrap/Importers/MissionCatalogImporter.cs b/SVSim.Bootstrap/Importers/MissionCatalogImporter.cs
new file mode 100644
index 0000000..ed7944b
--- /dev/null
+++ b/SVSim.Bootstrap/Importers/MissionCatalogImporter.cs
@@ -0,0 +1,57 @@
+using Microsoft.EntityFrameworkCore;
+using SVSim.Bootstrap.Models.Seed;
+using SVSim.Database;
+using SVSim.Database.Models;
+
+namespace SVSim.Bootstrap.Importers;
+
+/// <summary>
+/// Idempotent upsert of mission catalog rows from <c>seeds/mission-catalog.json</c>.
+/// Rows missing from the seed are LEFT INTACT (so hand-added catalog rows survive).
+/// </summary>
+public class MissionCatalogImporter
+{
+    public async Task<int> ImportAsync(SVSimDbContext context, string seedDir)
+    {
+        var seed = SeedLoader.LoadList<MissionCatalogSeed>(Path.Combine(seedDir, "mission-catalog.json"));
+        if (seed.Count == 0)
+        {
+            Console.WriteLine("[MissionCatalogImporter] No seed rows; skipping.");
+            return 0;
+        }
+
+        var existing = await context.MissionCatalog.ToDictionaryAsync(e => e.Id);
+        int created = 0, updated = 0;
+        var unmapped = new List<int>();
+        foreach (var s in seed)
+        {
+            if (s.Id == 0) continue;
+            var entry = existing.TryGetValue(s.Id, out var ex) ? ex : new MissionCatalogEntry { Id = s.Id };
+            entry.Name = s.Name;
+            entry.LotType = s.LotType;
+            entry.RequireNumber = s.RequireNumber;
+            entry.RewardType = s.RewardType;
+            entry.RewardDetailId = s.RewardDetailId;
+            entry.RewardNumber = s.RewardNumber;
+            entry.BattlePassPoint = s.BattlePassPoint;
+            entry.DefaultFlag = s.DefaultFlag;
+            entry.EventType = s.EventType;
+            entry.EventArg = s.EventArg;
+            entry.StartTime = s.StartTime;
+            entry.EndTime = s.EndTime;
+            if (ex is null) { context.MissionCatalog.Add(entry); existing[s.Id] = entry; created++; }
+            else updated++;
+            if (s.EventType is null) unmapped.Add(s.Id);
+        }
+
+        await context.SaveChangesAsync();
+        Console.WriteLine($"[MissionCatalogImporter] +{created}/~{updated}");
+        if (unmapped.Count > 0)
+        {
+            Console.WriteLine($"[MissionCatalogImporter] WARN: {unmapped.Count} mission_ids with " +
+                              $"no event_type: [{string.Join(", ", unmapped)}] — add to MISSION_EVENT_MAP " +
+                              "in data_dumps/extract/extract-missions.py and re-run the extractor");
+        }
+        return created + updated;
+    }
+}
diff --git a/SVSim.Bootstrap/Models/Seed/MissionCatalogSeed.cs b/SVSim.Bootstrap/Models/Seed/MissionCatalogSeed.cs
new file mode 100644
index 0000000..27554af
--- /dev/null
+++ b/SVSim.Bootstrap/Models/Seed/MissionCatalogSeed.cs
@@ -0,0 +1,21 @@
+using System.Text.Json.Serialization;
+
+namespace SVSim.Bootstrap.Models.Seed;
+
+/// <summary>Mirrors a single entry in <c>seeds/mission-catalog.json</c>.</summary>
+public sealed class MissionCatalogSeed
+{
+    [JsonPropertyName("id")] public int Id { get; set; }
+    [JsonPropertyName("name")] public string Name { get; set; } = "";
+    [JsonPropertyName("lot_type")] public int LotType { get; set; }
+    [JsonPropertyName("require_number")] public int RequireNumber { get; set; }
+    [JsonPropertyName("reward_type")] public int RewardType { get; set; }
+    [JsonPropertyName("reward_detail_id")] public long RewardDetailId { get; set; }
+    [JsonPropertyName("reward_number")] public int RewardNumber { get; set; }
+    [JsonPropertyName("battle_pass_point")] public int BattlePassPoint { get; set; }
+    [JsonPropertyName("default_flag")] public bool DefaultFlag { get; set; }
+    [JsonPropertyName("event_type")] public string? EventType { get; set; }
+    [JsonPropertyName("event_arg")] public int? EventArg { get; set; }
+    [JsonPropertyName("start_time")] public long StartTime { get; set; }
+    [JsonPropertyName("end_time")] public long? EndTime { get; set; }
+}
diff --git a/SVSim.UnitTests/Importers/MissionCatalogImporterTests.cs b/SVSim.UnitTests/Importers/MissionCatalogImporterTests.cs
new file mode 100644
index 0000000..bae3970
--- /dev/null
+++ b/SVSim.UnitTests/Importers/MissionCatalogImporterTests.cs
@@ -0,0 +1,91 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using SVSim.Bootstrap.Importers;
+using SVSim.Database;
+using SVSim.UnitTests.Infrastructure;
+
+namespace SVSim.UnitTests.Importers;
+
+public class MissionCatalogImporterTests
+{
+    private static string SeedDir => Path.Combine(AppContext.BaseDirectory, "Data", "seeds");
+
+    [Test]
+    public async Task Imports_captured_missions_from_seed()
+    {
+        using var factory = new SVSimTestFactory();
+        using var scope = factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+
+        await new MissionCatalogImporter().ImportAsync(db, SeedDir);
+
+        var rows = await db.MissionCatalog.OrderBy(e => e.Id).ToListAsync();
+        Assert.That(rows.Count, Is.GreaterThanOrEqualTo(5),
+            "captured mission_ids 12, 16, 20, 332, 505 must all be present");
+
+        var daily = rows.Single(r => r.Id == 332);
+        Assert.That(daily.LotType, Is.EqualTo(6));
+        Assert.That(daily.DefaultFlag, Is.True);
+        Assert.That(daily.EventType, Is.EqualTo("daily_match_win"));
+
+        var sword = rows.Single(r => r.Id == 16);
+        Assert.That(sword.LotType, Is.EqualTo(2));
+        Assert.That(sword.EventType, Is.EqualTo("ranked_win:swordcraft"));
+    }
+
+    [Test]
+    public async Task Is_idempotent_on_rerun()
+    {
+        using var factory = new SVSimTestFactory();
+        using var scope = factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+
+        await new MissionCatalogImporter().ImportAsync(db, SeedDir);
+        int before = await db.MissionCatalog.CountAsync();
+        await new MissionCatalogImporter().ImportAsync(db, SeedDir);
+        int after = await db.MissionCatalog.CountAsync();
+
+        Assert.That(after, Is.EqualTo(before));
+    }
+
+    [Test]
+    public async Task Leaves_existing_rows_untouched_when_missing_from_seed()
+    {
+        using var factory = new SVSimTestFactory();
+        using var scope = factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+
+        db.MissionCatalog.Add(new SVSim.Database.Models.MissionCatalogEntry
+        {
+            Id = 99999, Name = "preserved", LotType = 2,
+            RequireNumber = 1, RewardType = 9, RewardDetailId = 0, RewardNumber = 10,
+            BattlePassPoint = 0, DefaultFlag = false, StartTime = 0,
+        });
+        await db.SaveChangesAsync();
+
+        await new MissionCatalogImporter().ImportAsync(db, SeedDir);
+
+        var preserved = await db.MissionCatalog.FindAsync(99999);
+        Assert.That(preserved, Is.Not.Null);
+        Assert.That(preserved!.Name, Is.EqualTo("preserved"));
+    }
+
+    [Test]
+    public async Task Empty_seed_is_no_op()
+    {
+        using var factory = new SVSimTestFactory();
+        using var scope = factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<SVSimDbContext>();
+
+        string tmp = Path.Combine(Path.GetTempPath(), $"seed-{Guid.NewGuid()}");
+        Directory.CreateDirectory(tmp);
+        try
+        {
+            File.WriteAllText(Path.Combine(tmp, "mission-catalog.json"), "[]");
+            await new MissionCatalogImporter().ImportAsync(db, tmp);
+            int count = await db.MissionCatalog.CountAsync();
+            Assert.That(count, Is.EqualTo(0));
+        }
+        finally { Directory.Delete(tmp, true); }
+    }
+}