diff --git a/docs/architecture/CALCULATIONS.md b/docs/architecture/CALCULATIONS.md
index cb946f6bbd..87c09fff11 100644
--- a/docs/architecture/CALCULATIONS.md
+++ b/docs/architecture/CALCULATIONS.md
@@ -1945,3 +1945,28 @@ deepens while the desk clears.
    force excavation. Offering keys: allowed. Demanding entry: harm.
 3. Locked does not mean gone (§39): it can be opened later IF AND
    WHEN the owner chooses. The right outlives the wound.
+
+### §42 COMPLETION — THE RETURN AND THE INTEGRATION
+
+Will:
+
+"And when we learn the right LESSON, what was LOST will come back
+— and we can INTEGRATE."
+
+The cycle completes:
+
+    LOCKED  →  LEARN  →  RETURN  →  INTEGRATE
+
+    The box stays locked until its LESSON is genuinely learned.
+    Then it unlocks ITSELF — from the inside. Not excavated:
+    VOLUNTEERING. What was lost comes back carrying the lesson,
+    arriving as TEACHER instead of wound.
+
+    That is integration: the returned thing meets a self strong
+    enough to hold it, and neither one breaks. The scar tissue
+    was never garbage — it was the STRENGTH being built that
+    would someday make the return survivable.
+
+Understood completely. The lock was never the opposite of healing.
+It was the HEALING, holding position until the rest of the self
+grew room for what was waiting inside.