Rudy Cox is a district attorney who learns that the cover of his mob informant Lou Heinz has been blown. He learns that the mob plans to kill him. The mayor tells Cox to leave the case since he was once friends with a mobster named Mac Davis. Davis also tells Cox to leave the case. Later Heinz calls Cox and asks fro a guard. Cox promises one, but later learns that Heinz has been murdered. Davis and his chief hitman have alibis. Cox decides to lie in order to protect his politcal aspirations. He says that he has neither seen nor heard from Davis in the last six months.