Dispatched by his boss to find a suitable candidate to perform the contract killing of the Hong Kong boss of a rival gang, Ishioka (Tarumi) chances upon a penniless down-on-his-luck young man named Nakata (Akagi) nursing a scotch in a snazzy drinking joint. With Ishioka left out of action with a prosthetic arm after a former job has gone wrong, he now acts as a trainer for would-be hitmen, taking them into the household he shares with his blind sister Kikuyo (Sasamori) and training them up as efficient killing machines. As his protégé, the charming Nakata is particularly quick to learn how to wield a Colt 45, and the success of the mission seems assured. As Kikuyo begins falling for their new lodger, Nakata pledges to use his fee to send her for an operation with an eye specialist in Kobe. But complications set in when Nakata becomes reacquainted with Chikako (Shiraki), a damsel in distress whom he gallantly rescued from a group of hoods in an early scene. It soon transpires that neither Nakata nor Chikako are exactly who they seem.