Zen Mikami, a Special Agent from the US, is assigned to rookie Seiichi Kiriyama from the Tokyo Metropolitan Police. But he's surprised when he meets Kiriyama in a cell in the police's underground prison. Kiriyama, a criminal, uses his sharp intellect to solve cases in return for a reduced sentence. Though as they start working together, he's thrown off by Mikami's brusque, rule-breaking style.