In 1960s Chicago, Lt. Mike Torello and the members of his Major Crime Unit carry on a near-epic battle against organized crime figures such as Ray Luca.
After his murder mistrial, Luca clashes with a crime kingpin over plans to split up control of the sinking Luca gambling empire.
Empire builder Luca's jubilation over his growing business turns to fear that his associates are setting him up.
Luca's determination to add another casino to his gambling organization brings his empire to the brink of collapse.
A child molestation charge against one of Torello's colleagues jeopardizes the unit's investigation of Luca.