Supposedly it's the sins of the father that are visited upon the sons, but in the case of mild-mannered news reporter Frank Merson it's the sins of his twin brother Fred that have come to rest squarely on his shoulders. Over the years Frank has grown quite accustomed to being mistaken for Fred - usually by some fist-swinging husband whose wife is dallying with fast Freddy.
So when someone slugs Frank in the bar car of a Long Island commuter train, he naturally assumes Fred is up to his old shenanigans. But alas, Fred's latest involvements are anything but romantic: they include a corpse, stolen art, and a gangster named Tommy ("St. Thomas") d'Aquinas. Frank's only hope is to locate frère Fred, and soon - or face the deadly consequences.