Ayumi runs into a purse-snatcher and the man pursuing them, Kume Shosaku. The other Detective Boys arrive, and while they're being filled in, a body is discovered in the apartment complex the culprit fled into. Next to the body are the jacket the culprit was wearing and the bag they stole. However, the money is missing from inside the bag, and the dead man doesn't look like the culprit. Meanwhile, Inspector Megure receives a call that the body of a man who has Kume's wallet and 300,000 yen has been discovered.
