"I'm curious." Chitanda Eru muttered softly after watching the class-produced independent film to be shown at the cultural festival. At the end of that movie, a victim died in a locked ruins room. Who was the murderer? What was the modus operandi? The movie ends without any explanation at all. Chitanda, who was concerned about the follow-up, began to explore the ending together with her partner Oreki Houtaro and others.
