Mike Shannon is used to taking on the hard cases. He's a private investigator and ex-cop in St. Louis, and when the authorities throw up their hands, Shannon is there to bring the guilty to justice. But doing what's right doesn't mean keeping your hands clean: he's stacked up quite a body count over the years-something he's not proud of-and it's beginning to take its toll on him. When a teenage girl goes missing, Shannon takes what he believes will be a simple case. But when he finds cocaine hidden in the girl's bedroom-cocaine that apparently came from the police department's evidence room-things begin to get complicated. Things get even worse when Shannon begins to suspect his own ex-partner, who was brutally murdered, may be linked to the girl's disappearance and the stolen drugs. Shannon's investigation of a possible runaway is shaping up into one hell of a case against police corruption and drug trafficking. As Shannon digs deeper, the danger escalates when he comes face to face with a dark figure from his past, a rogue CIA hitman known as the Sandman. Shannon might be in over his head, but that's never stopped him before. In all the confusion, Shannon is sure of one thing, he's not done killing yet. As Shannon's past catches up with him, his two worlds collide and the dead bodies begin to litter the streets of St. Louis, with a trail of blood leading downtown to the Arch, The Gateway to Hell.