The Flash stops a robbery but the culprits get away after shooting a guard, and The Flash chooses to save the man instead of following the criminals. Joe shows Barry a book of suspects and Barry identifies Leonard Snart as the leader of the group. Snart revises his plan to steal the Kahndaq Dynasty Diamond and gets a boost when he gets his hands on a stolen "cold gun," which could kill The Flash. Dr. Wells is furious when he finds out that Cisco built the cold gun without telling anyone and now it's missing. Meanwhile, Iris is getting the silent treatment from Joe because of her relationship with Eddie.