diff --git a/D03_PlanAnalysis/D03_PlanAnalysis_UI_Draw.ts b/D03_PlanAnalysis/D03_PlanAnalysis_UI_Draw.ts
index 02d0791d7..acaa42994 100644
--- a/D03_PlanAnalysis/D03_PlanAnalysis_UI_Draw.ts
+++ b/D03_PlanAnalysis/D03_PlanAnalysis_UI_Draw.ts
@@ -48,6 +48,7 @@ import {
   type PlanNetwork,
   type Vertex,
 } from "./logic/D03_PlanAnalysis_Plan";
+import { joinTouching } from "./logic/D03_PlanAnalysis_OneLine";
 import { isMiddleNode, nodeRecord, rejoinMiss, rejoinSpan } from "./logic/D03_PlanAnalysis_Span";
 import {
   fmt,
@@ -188,7 +189,7 @@ export function createPlanDraw(params: PlanDrawParams): PlanDraw {
     return vertices[vertices.length - 1] ?? null;
   };
 
-  /** 붙을 자리 — 그리는 선 첫 점 아닌 지점 · 다른 선 꺾임점 · 다른 선 위(그리는 선 빼고). */
+  /** 붙을 자리 — 그리는 선 첫 점 아닌 지점 · 다른 선 꺾임점 · 다른 선 위(그리는 선 빼고) · 한 선 페이지 = 다른 토막 끝만(774-2). */
   function snapAt(
     px: number,
     py: number,
@@ -200,16 +201,20 @@ export function createPlanDraw(params: PlanDrawParams): PlanDraw {
       .filter((point) => !head || !samePoint(point, head))
       .map((point) => ({ point, note: "지점에 붙음" }));
     for (const point of params.snaps?.() ?? []) offers.push({ point, note: "이음점에 붙음" });
+    const one = !featureOn(params.page, "branch");
     network.lines.forEach((line, i) => {
       if (i !== active)
-        for (const point of line.vertices) offers.push({ point, note: "선 꺾임점에 붙음" });
+        line.vertices.forEach((point, k) => {
+          if (!one || k === 0 || k === line.vertices.length - 1)
+            offers.push({ point, note: one ? "끊긴 끝에 이음" : "선 꺾임점에 붙음" });
+        });
     });
     const best = offers
       .map((offer) => ({ ...offer, gap: screenGap(map, offer.point, px, py) }))
       .filter((offer) => offer.gap <= SNAP_PX)
       .sort((a, b) => a.gap - b.gap)[0];
     if (best) return { point: best.point, note: best.note, onLine: null };
-    const hit = lineAt(network, px, py, map, active);
+    const hit = one ? null : lineAt(network, px, py, map, active);
     return hit
       ? { point: hit.point, note: "선 위에 붙음", onLine: { line: hit.line, segment: hit.segment } }
       : null;
@@ -331,6 +336,7 @@ export function createPlanDraw(params: PlanDrawParams): PlanDraw {
           if (typeof joined !== "string" && joined !== turned) network = joined;
         }
       }
+      if (!featureOn(params.page, "branch")) network = joinTouching(network); // B05 = 늘 노선 하나(774-2)
       if (network !== params.network()) params.commit(network);
     }
     active = null;
diff --git a/D03_PlanAnalysis/logic/D03_PlanAnalysis_OneLine.ts b/D03_PlanAnalysis/logic/D03_PlanAnalysis_OneLine.ts
new file mode 100644
index 000000000..6eda6acb7
--- /dev/null
+++ b/D03_PlanAnalysis/logic/D03_PlanAnalysis_OneLine.ts
@@ -0,0 +1,37 @@
+/* =============================================================================
+ * D03_PlanAnalysis_OneLine.ts
+ * 한 선 페이지(B05 · 기능 표 「branch」 숨김) 예정노선 = 늘 노선 하나(PLAN 774-2 · 요구 618).
+ *   `joinTouching` = 끝이 맞닿은 토막을 한 선으로 이음(꼬리 ↔ 머리 · 꼬리 ↔ 꼬리 · 머리 ↔ 머리 = 뒤집어 맞춤) ·
+ *   갈래 · 점 하나 선은 안 건드림 · 남는 id = 앞 토막(`attachHead` 규칙). 노선 여럿 = D 그룹(D03)만.
+ *   DOM · fetch · sessionStorage 없음.
+ * ========================================================================== */
+
+import { attachHead, reverseLine, samePoint, type PlanNetwork } from "./D03_PlanAnalysis_Plan";
+
+/** 끝이 맞닿은 토막을 모두 이어 한 선으로 — 못 이을 것만 남김. */
+export function joinTouching(network: PlanNetwork): PlanNetwork {
+  let next = network;
+  for (let again = true; again;) {
+    again = false;
+    const ends = next.lines.map((line) =>
+      line.vertices.length > 1 && !line.branch ? [line.vertices[0], line.vertices.at(-1)!] : null,
+    );
+    for (let i = 0; i < ends.length && !again; i += 1)
+      for (let j = 0; j < ends.length && !again; j += 1) {
+        const [a, b] = [ends[i], ends[j]];
+        if (i === j || !a || !b) continue;
+        // j 머리가 i 꼬리에 오게 맞춤
+        const turned = samePoint(a[1], b[0])
+          ? next
+          : samePoint(a[1], b[1])
+            ? reverseLine(next, j)
+            : samePoint(a[0], b[0])
+              ? reverseLine(next, i)
+              : null;
+        if (!turned || typeof turned === "string") continue;
+        const joined = attachHead(turned, j);
+        if (joined !== turned) [next, again] = [joined, true];
+      }
+  }
+  return next;
+}
diff --git a/resources/tester/test_771_2_rejoin_span.py b/resources/tester/test_771_2_rejoin_span.py
index 461f79bc2..542b6a87e 100644
--- a/resources/tester/test_771_2_rejoin_span.py
+++ b/resources/tester/test_771_2_rejoin_span.py
@@ -3,6 +3,7 @@
 중간 노드에서 그은 점이 같은 선 다른 노드에 닿음 = 두 노드 사이 옛 구간을 새 점으로 갈음 · 한 줄 그대로 ·
 거꾸로(앞 노드에 닿음) = 점 차례 뒤집어 넣음 · 같은 노드 = 까닭 글(꼴 그대로) · 끝점에 닿음 = 끝까지 갈음 ·
 노드 기록 = 꼭짓점과 같은 길이.
+774-2(요구 618) B05 = 늘 노선 하나 `logic/D03_PlanAnalysis_OneLine.ts` `joinTouching` = 맞닿은 토막 이음.
 774-1(요구 616) 끝 판정 `rejoinMiss` = 다른 중간 노드만 끝 · 시작 노드 · 끝점 = 계속 긋기 까닭 글 · 시작 = 중간 노드만.
 
 ./venv/Scripts/python.exe -m pytest resources/tester/test_771_2_rejoin_span.py -q
@@ -17,12 +18,22 @@ from pathlib import Path
 
 ROOT = Path(__file__).resolve().parents[2]
 TS_FILE = ROOT / "D03_PlanAnalysis" / "logic" / "D03_PlanAnalysis_Span.ts"
+ONE_FILE = ROOT / "D03_PlanAnalysis" / "logic" / "D03_PlanAnalysis_OneLine.ts"
 TSC = ROOT / "config" / "node_modules" / "typescript" / "bin" / "tsc"
 
 _RUNNER = """
 import { writeFileSync } from "node:fs";
 import * as plan from "./D03_PlanAnalysis/logic/D03_PlanAnalysis_Plan.js";
 import * as span from "./D03_PlanAnalysis/logic/D03_PlanAnalysis_Span.js";
+import * as one from "./D03_PlanAnalysis/logic/D03_PlanAnalysis_OneLine.js";
+const two = (a, b) => {
+  let m = plan.newLine(plan.emptyNetwork(), a[0]);
+  for (const p of a.slice(1)) m = plan.appendVertex(m, 0, p);
+  m = plan.newLine(m, b[0]);
+  for (const p of b.slice(1)) m = plan.appendVertex(m, 1, p);
+  return m;
+};
+const flat = (m) => m.lines.map((l) => l.vertices);
 let n = plan.newLine(plan.emptyNetwork(), [0, 0]);
 for (const p of [[100, 0], [200, 0], [300, 0], [400, 0]]) n = plan.appendVertex(n, 0, p);
 const L = span.nodeRecord("length", 20, 9);
@@ -41,6 +52,11 @@ writeFileSync(
     middle: [0, 1, 2, 3, 4].map((v) => span.isMiddleNode(5, v)),
     tip_text: span.REJOIN_TIP,
     hold_text: span.REJOIN_HOLD,
+    join_tail_head: flat(one.joinTouching(two([[0, 0], [1, 0]], [[1, 0], [2, 0]]))),
+    join_tail_tail: flat(one.joinTouching(two([[0, 0], [1, 0]], [[2, 0], [1, 0]]))),
+    join_head_head: flat(one.joinTouching(two([[1, 0], [0, 0]], [[1, 0], [2, 0]]))),
+    join_apart: flat(one.joinTouching(two([[0, 0], [1, 0]], [[5, 0], [6, 0]]))),
+    join_branch: flat(one.joinTouching(plan.appendVertex(plan.addBranch(n, 0, 2), 1, [200, 50]))),
   }),
 );
 """
@@ -53,6 +69,7 @@ def _run_ts(tmp_path: Path) -> dict:
             "node",
             str(TSC),
             str(TS_FILE),
+            str(ONE_FILE),
             "--outDir",
             str(out),
             "--rootDir",
@@ -122,3 +139,13 @@ def test_end_only_other_middle_node(tmp_path: Path) -> None:
     assert r["miss"] == [None, None, hold, tip, tip, None]
     assert "중간 노드" in tip and "중간 노드" in hold
     assert r["middle"] == [False, True, True, True, False]
+
+
+def test_one_line_join_touching(tmp_path: Path) -> None:
+    """774-2 — 맞닿은 두 토막 = 한 선(어느 끝이든 · 차례 이어짐) · 떨어진 토막 · 갈래 = 그대로."""
+    r = _run_ts(tmp_path)
+    assert r["join_tail_head"] == [[[0, 0], [1, 0], [2, 0]]]
+    assert r["join_tail_tail"] == [[[0, 0], [1, 0], [2, 0]]]
+    assert r["join_head_head"] in ([[[0, 0], [1, 0], [2, 0]]], [[[2, 0], [1, 0], [0, 0]]])
+    assert len(r["join_apart"]) == 2
+    assert len(r["join_branch"]) == 2  # 갈래(D03 꼴)는 안 이음