An undercover federal cop called Charlie (Liam Neeson) is constantly blighted by job stress, has chronic gastrointestinal difficulties, suffers from nightmares, and worries that the bad guys are going to see the terror in his eyes while trapped in a deadly sting operation.
Two portraits, are carried in this film. The first is that of undercover federal cop, Charlie Mayough (Liam Neeson), then there's the hapless, impulsive Fulvio Nesstra (Oliver Platt), a one-time hitman for the Mafia who has moved up into a management slot for a crime family on the strength of marital ties.
While Charlie pretends to be a crooked broker who helps crime syndicates launder ill-gotten profits through the stock market, Fulvio is the overwhelmed, slow-witted representative of a tough don who also happens to be his father-in-law.
Constantly humiliated by his sneering wife, Gloria (Mary McCormack) and openly despised by the family patriarch, Fulvio stifles his rage at home but takes it, quite willingly into his dealings with Colombian traffikers (one of whom he shoots just for making a crack about Fulvio's urinary problems).
Meanwhile Charlie struggles to keep the partnership between gangsters and drug kingpins together, and Fulvio - normally a miserable loner - becomes drawn to Charlie's enviable intelligence and apparent over confidence.
What he doesn't see, however, is that Charlie is privately falling apart from too much time spent in the underworld.
Despite all this, the two men become quite friendly, and the script implies that Charlie and Fulvio even have much in common. For one thing, they're both posing, i.e., Charlie as a crook, Fulvio as a businessman. They both yearn to feel more alive, and they're both terribly frightened of being exposed as frauds.