It's 1931 and Mike Peeters, a hitman for the mob, has a contract to murder Al Capone's traitorous accountant and a talkative stoolie. When a young couple witness the crime, Mike coerces them into becoming his protégés. As Mike prepares for his next contract-the murder of Al Capone-he introduces Gus and Hannah to the seamy underworld of the mob. But someone is on to his plans. As Mike eludes attempts on his own life, Gus and Hannah are drawn deeper and deeper into a dangerous world of snitches, dirty cops, labor rackets, and vicious warfare between mobster gangs. Just below the surface is the attraction between Mike and the woman he has taken under his wing. As he races to identify the snitch who hounds him, he hopes it's not Hannah he'll have to murder in the end.