Mike takes a job chauffeuring loanshark Jack Shannon, but begins to have doubts about the wisdom of doing so after Grizz and Marcellus warn him that he's headed down a slippery slope. After he's goaded into beating up a man to collect on a debt for Shannon, Mike realizes that his friends are right that he's headed for trouble, and tells Shannon he's quitting. Shannon tries to entice him to stay by offering to call in a favor with the District Attorney and have the case which led to Mike's dismissal from the force thrown out. Although he's sorely tempted, Mike turns Shannon down. After Mike leaves, Marcellus appears and is greeted warmly by Shannon.

After Marcellus frames bookie Nick Bennett for smuggling guns and Bennett's wife asks Mike to help clear him, Mike discovers that Jack Shannon is blackmailing Marcellus and using him to extort Bennett. Mike arranges a sit-down between Bennett and Shannon, tricks Shannon into confessing to a crime, and uses the confession which Marcellus has captured on tape to blackmail Shannon into cutting Bennett and Marcellus loose.