When small time Irish hood, Shawn Murphy, goes to work for Lawrence, Massachusetts Mafia boss Sonny Pentola, he soon finds he might have gotten more than he bargained for. Shawn quickly earns rank and Sonny's trust when he saves Sonny from an assassination attempt. Sonny makes him a trusted liaison in a large development deal with Irish associates in Boston. Their world quickly spirals out of control as more assassination attempts occur, and the entire area comes to the brink of a Mob war. With the development becoming delayed, and millions at stake, it begins to look as if Sonny has lost control of his mandated territory; and the Mafia begins to lose faith in Sonny's capabilities. With the risk of losing his territory, Sonny seeks furiously to find the truth. Great Loyalty and Great Betrayal materialize as a sinister conspiracy against Sonny is unveiled.