After the DA's office loses a major white collar crime case, ADA Stone wants to know what happened to key prosecution evidence, computer disks with financial data that were wiped clean. Stone blames the police and is certain someone on the force was paid to destroy the evidence. Internal Affairs takes charge of the case and Captain Cragan is one of several policemen under suspicion. Greevy and Logan decide to help out their Captain by investigating the matter themselves. They find an anomaly in the duty rosters that indicate a retired policeman was on duty in the secure evidence lock-up two weeks after he retired. For Cragan, the biggest challenge is that a former Chief, his mentor who was responsible for his advancement in the force, is likely implicated in the case. Stone wants him, to wear a wire to get the evidence he needs to convict.
—garykmcd