Inspector Zhang from the Singapore Police Force is called to a case that at first did not seem worth a damn. A young woman was killed during a burglary. Fingerprints on the murder weapon point to a known burglar, and bite marks on the victim's hand. But the robber has an ironclad alibi, as he was in police custody at the time of the murder. The Deputy Commissioner asks Inspector Zhang to find out how the robber managed to get out of the locked cell, but this is easier said than done, and the inspector's deductive abilities are put to another test by this strange a mystery.