Neal is called down to an expensive boutique to investigate the theft of the most exotic pink diamond in the world. The diamond was supposed to be on display as part of a promotional event, but the manager got nervous when security footage showed a masked man breaking into the boutique vault. Neal's examination of the stone confirms the manager's suspicions; someone has replaced the diamond with a high quality forgery.
Neal and Peter race back to headquarters to pull suspects, but they get an unwelcome surprise in the form of Garrett Fowler from the Office of Professional Responsibility. The FBI's version of Internal Affairs, the OPR says they're in town to conduct a standard review. In reality, Fowler is looking into the same diamond heist and he has already found his prime suspect -Neal.
Peter is immediately dismissive, but Fowler makes a compelling case. Neal was one of a handful of people with the inside information to pull off the job, and even more incriminatingly, his tracking anklet went dark for six hours on the night of the heist.