One of Sam's first profiles resulted in a man being sentenced to death. Ten years later when the man is about to be executed, murders begin happening that match the m.o. of the prior killings. Ballistics evidence proves the same gun was used for all the crimes. Sam, feeling culpable for what might have been a deadly mistake, reopens the investigation. Evidence leads to a lowly bicycle courier who is mortally wounded when he resists arrest. Once the dying man is in custody, the death row inmate is released from prison. Though a wrong seem to have been righted, Sam still feels something is amiss. A chess set is found in the prisoner's cell helps her to realize that the whole thing was an elaborate ruse. The man originally convicted was indeed the first killer. The second killer was only a pawn doing his bidding. Sam, Bailey, and the team re-arrest the now pardoned killer at the hospital bed of his wounded puppet, just as he attempts to kill the only loose end in his elaborate plan.