Beckett's team investigate an ice cream man's murder and find evidence that a child may have been a witness, so Castle goes undercover at a local school's second-grade class to find them. They eventually discover that the case is connected to a fake passport ring and a wanted war criminal who sought to escape the country using a fake passport. However, the leader of the ring was a surviving victim of the man and recognized and sought to bring him down. Beckett and Castle are able to locate a picture of the culprit and apprehend him, turning the killer over to the International Criminal Court for trial for his numerous crimes.