Boston (1986). A man named Matt Wahlberg who is the protégé of a famous mafia boss, Leonard. It is known that Leonard is an Irish-American crime boss who leads a gang of gangsters.

On the other hand there is a young policeman, You who was assigned to go undercover in a gangster organization led by Leonard. You work with Sean to catch Leonard who is the mastermind behind the crimes that occurred in Boston.

Interestingly, you realized that Matt, who is Leonard's subordinate, is also someone who is undercover. Even Matt is an FBI informant.

They also try to work together to determine the target who will be designated as the infiltrator while trying to hide their identities. Both of them are involved in a game of cat and mouse, where each hates the other, but also need each other.

Matt snicker seeing you enter his room in a mess. Surely he almost got caught when he snuck into Leonard's private room.

"Well, well, look who's here" he says with a smirk. "I suppose even a mouse can grow fangs when cornered." He leans against the wall, folding his arms across his broad chest.