diff --git a/internal/plugin/zone_graph_manor_blackspire.go b/internal/plugin/zone_graph_manor_blackspire.go
new file mode 100644
index 0000000..2087a82
--- /dev/null
+++ b/internal/plugin/zone_graph_manor_blackspire.go
@@ -0,0 +1,82 @@
+package plugin
+
+// Phase G8d — Haunted Manor of Blackspire branching graph.
+//
+// T3 zone. Shape: stacked 3-way "hub" forks. The plan calls T2+ for
+// "two forks", and a Manor of corridors and locked doors fits a wide-
+// fork hub-and-spoke pattern more naturally than a binary fork. Two
+// hub nodes (great_hall, upper_hall), each with three options:
+//
+//   entry → foyer → great_hall (3-way)
+//                      ├─[unlocked]── portrait_gallery ─┐
+//                      ├─[Perception DC 14]── study ────┼── upper_hall (3-way)
+//                      └─[INT DC 14]── library ─────────┘     ├─[unlocked]── master_bedroom (elite) → boss
+//                                                              ├─[Perception DC 15]── hidden_oratory (secret) → boss
+//                                                              └─[LevelMin 7]── tower_observatory → boss
+//
+// Two consecutive 3-way fork prompts make this the first zone where
+// the player picks twice in a row from a wide menu — distinct from the
+// binary forks of G8a/b and the parallel Y-trees of G8c. Exercises
+// LockLevelMin (first authored use) so all four non-trivial lock kinds
+// (Perception, StatCheck, LevelMin, plus implicit LockNone) appear by
+// G8d.
+
+func zoneManorBlackspireGraph() ZoneGraph {
+	nodes := []ZoneNode{
+		{NodeID: "manor_blackspire.entry", Kind: NodeKindEntry, IsEntry: true,
+			Label: "Manor Gate", PosX: 0, PosY: 2},
+		{NodeID: "manor_blackspire.foyer", Kind: NodeKindExploration,
+			Label: "Foyer", PosX: 1, PosY: 2},
+		{NodeID: "manor_blackspire.great_hall", Kind: NodeKindFork,
+			Label: "Great Hall", PosX: 2, PosY: 2},
+		{NodeID: "manor_blackspire.portrait_gallery", Kind: NodeKindExploration,
+			Label: "Portrait Gallery", PosX: 3, PosY: 1},
+		{NodeID: "manor_blackspire.study", Kind: NodeKindExploration,
+			Label: "Locked Study", PosX: 3, PosY: 2},
+		{NodeID: "manor_blackspire.library", Kind: NodeKindExploration,
+			Label: "Forbidden Library", PosX: 3, PosY: 3},
+		{NodeID: "manor_blackspire.upper_hall", Kind: NodeKindFork,
+			Label: "Upper Hall", PosX: 4, PosY: 2},
+		{NodeID: "manor_blackspire.master_bedroom", Kind: NodeKindElite,
+			Label: "Master Bedroom", PosX: 5, PosY: 1},
+		{NodeID: "manor_blackspire.tower_observatory", Kind: NodeKindExploration,
+			Label: "Tower Observatory", PosX: 5, PosY: 2},
+		{NodeID: "manor_blackspire.hidden_oratory", Kind: NodeKindSecret,
+			Label: "Hidden Oratory", PosX: 5, PosY: 3,
+			Content: ZoneNodeContent{LootBias: 2.0}},
+		{NodeID: "manor_blackspire.boss", Kind: NodeKindBoss, IsBoss: true,
+			Label: "Aldric's Sanctum", PosX: 6, PosY: 2},
+	}
+	edges := []ZoneEdge{
+		{From: "manor_blackspire.entry", To: "manor_blackspire.foyer", Lock: LockNone},
+		{From: "manor_blackspire.foyer", To: "manor_blackspire.great_hall", Lock: LockNone},
+		// Great Hall — 3-way: portrait (open), study (perception), library (intelligence)
+		{From: "manor_blackspire.great_hall", To: "manor_blackspire.portrait_gallery", Lock: LockNone, Weight: 1},
+		{From: "manor_blackspire.great_hall", To: "manor_blackspire.study",
+			Lock: LockPerception, LockData: map[string]any{"dc": 14},
+			Hint: "an out-of-place draft from a doorframe", Weight: 2},
+		{From: "manor_blackspire.great_hall", To: "manor_blackspire.library",
+			Lock: LockStatCheck, LockData: map[string]any{"stat": "INT", "dc": 14},
+			Hint: "a runed door — you'd need to read it", Weight: 2},
+		// All three converge at upper_hall.
+		{From: "manor_blackspire.portrait_gallery", To: "manor_blackspire.upper_hall", Lock: LockNone},
+		{From: "manor_blackspire.study", To: "manor_blackspire.upper_hall", Lock: LockNone},
+		{From: "manor_blackspire.library", To: "manor_blackspire.upper_hall", Lock: LockNone},
+		// Upper Hall — 3-way: master_bedroom (open elite), hidden_oratory (high perception secret), tower (level-gated)
+		{From: "manor_blackspire.upper_hall", To: "manor_blackspire.master_bedroom", Lock: LockNone, Weight: 1},
+		{From: "manor_blackspire.upper_hall", To: "manor_blackspire.hidden_oratory",
+			Lock: LockPerception, LockData: map[string]any{"dc": 15},
+			Hint: "a candle behind a panel that shouldn't have a back", Weight: 2},
+		{From: "manor_blackspire.upper_hall", To: "manor_blackspire.tower_observatory",
+			Lock: LockLevelMin, LockData: map[string]any{"min_level": 7},
+			Hint: "a spiral stair that creaks ominously — climb only if you trust your footing", Weight: 3},
+		{From: "manor_blackspire.master_bedroom", To: "manor_blackspire.boss", Lock: LockNone},
+		{From: "manor_blackspire.hidden_oratory", To: "manor_blackspire.boss", Lock: LockNone},
+		{From: "manor_blackspire.tower_observatory", To: "manor_blackspire.boss", Lock: LockNone},
+	}
+	return BuildGraph(ZoneManorBlackspire, nodes, edges)
+}
+
+func init() {
+	registerZoneGraph(zoneManorBlackspireGraph())
+}
diff --git a/internal/plugin/zone_graph_manor_blackspire_test.go b/internal/plugin/zone_graph_manor_blackspire_test.go
new file mode 100644
index 0000000..6c1c686
--- /dev/null
+++ b/internal/plugin/zone_graph_manor_blackspire_test.go
@@ -0,0 +1,71 @@
+package plugin
+
+import "testing"
+
+func TestManorBlackspireGraph_Registered(t *testing.T) {
+	g, ok := zoneGraphRegistry[ZoneManorBlackspire]
+	if !ok {
+		t.Fatal("zoneManorBlackspireGraph not registered")
+	}
+	if g.Entry != "manor_blackspire.entry" {
+		t.Errorf("entry node = %q", g.Entry)
+	}
+	if len(g.Nodes) != 11 {
+		t.Errorf("nodes = %d, want 11", len(g.Nodes))
+	}
+}
+
+// TestManorBlackspireGraph_TwoStackedThreeWayForks captures the design
+// shape: both great_hall and upper_hall expose three options.
+func TestManorBlackspireGraph_TwoStackedThreeWayForks(t *testing.T) {
+	g := zoneManorBlackspireGraph()
+	for _, hub := range []string{
+		"manor_blackspire.great_hall",
+		"manor_blackspire.upper_hall",
+	} {
+		outs := g.outgoingEdges(hub)
+		if len(outs) != 3 {
+			t.Errorf("%s outgoing = %d, want 3", hub, len(outs))
+		}
+	}
+}
+
+func TestManorBlackspireGraph_AllSpokesReachBoss(t *testing.T) {
+	g := zoneManorBlackspireGraph()
+	for _, leaf := range []string{
+		"manor_blackspire.master_bedroom",
+		"manor_blackspire.tower_observatory",
+		"manor_blackspire.hidden_oratory",
+		"manor_blackspire.portrait_gallery",
+		"manor_blackspire.study",
+		"manor_blackspire.library",
+	} {
+		if !reachable(g, leaf, "manor_blackspire.boss") {
+			t.Errorf("%s unreachable to boss", leaf)
+		}
+	}
+}
+
+// TestManorBlackspireGraph_LockLevelMinFirstUse verifies this zone is
+// the first to author LockLevelMin, completing lock-kind coverage
+// (Perception, StatCheck, LevelMin, LockNone) by G8d.
+func TestManorBlackspireGraph_LockLevelMinFirstUse(t *testing.T) {
+	g := zoneManorBlackspireGraph()
+	var levelMinEdge *ZoneEdge
+	for _, outs := range g.Edges {
+		for i := range outs {
+			if outs[i].Lock == LockLevelMin {
+				levelMinEdge = &outs[i]
+			}
+		}
+	}
+	if levelMinEdge == nil {
+		t.Fatal("expected at least one LockLevelMin edge")
+	}
+	if min := lockDataInt(levelMinEdge.LockData, "min_level", 0); min < 7 {
+		t.Errorf("min_level = %d, want >= 7 (T3 zone)", min)
+	}
+	if levelMinEdge.Hint == "" {
+		t.Error("level-gated edge missing hint")
+	}
+}