Daiba Jin, also known as "Daimajin", is a hot-blooded ace in the First Criminal Investigation Division who rushes to crime scenes before anyone else. However, Daiba has a secret - he has killed a criminal with his own hands. After the secret was discovered by his chief Hirayasu Saimon, Daiba, under Hirayasu's order, is forced to transfer to a special task force specializing in unsolved cases and secretly deals with criminals whom the police cannot touch.