The murders of an Elvis impersonator and a rook bird seem to be unrelated until Greg realizes the victims, a "king" and a "rook", are meant to signify chess pieces. The CSIs trace the moss found on the body to a hotel hosting a chess tournament as part of a multi-city tour. The CSIs discover other chess-related kills that took place in the last few cities of the tour and determine the murders are meant to emulate chess moves. After speaking to his old chess mentor, Paul Lomax, Greg learns the killer is mimicking the moves of a championship match played 16 years ago. They question the winner of the game, Karl Schrute, who reveals he recently received an odd papier-mache bishop.The papier-mache materials lead them to Lee Crosby, a recently released prison inmate obsessed with Troy Parker, the loser of the game. When the murder of a costumed knight diverges from the pattern of the game, a print left at the scene is identified as Parker's. The CSIs track down Parker's motel room and find Crosby dead, believing that Parker treated Crosby as a pawn. Soon after, Schrute goes missing and the CSIs are thrown for a loop when a print found on drug vials containing Parker's dementia medication matches Lomax. While being interrogated, Lomax drops a hint to Greg which leads them to Jenny Carroll, the organizer of the chess tournament who is found to be hiding Schrute and Parker in a storage facility. Motivated by her father's disdain for female chess players, she replayed the match the way it should have been played to show the world the power of the "queen".