A robbery and murder occurred at a gas station facing the national highway at 1:00am. Detectives Nagata, head of the First Investigation Division, begins investigating. Two bullets were removed from the corpse of a staff member on duty at the station, and the last car to be refilled with gasoline, Sakura Taxi No. 5-E1044, appears on the line of investigation. The same night, a robbery murder case was discovered using the same US military gun that was used on the gas station victim.