diff --git a/server/api/story/[id]/index.put.ts b/server/api/story/[id]/index.put.ts
index 1407938..0765362 100644
--- a/server/api/story/[id]/index.put.ts
+++ b/server/api/story/[id]/index.put.ts
@@ -33,7 +33,7 @@ export default eventHandler(async (ev) => {
 	const update: Partial<IStory> = {
 		title: body.title,
 		completed: body.completed,
-		coAuthor: body.coAuthor,
+		coAuthor: !!body.coAuthor ? body.coAuthor : null,
 		chapters: [],
 	};
 	for (const oc of os.chapters) {