Kirk arranges for the "Enterprise" to ferry the acting troupe to its next destination. He transfers Lt. Kevin Riley to Engineering, after discovering that he too was a witness to the Tarsus IV massacre. These actions arouse the curiosity of First Officer Spock, who, after an investigation of his own, learns the history of the massacre, Kirk and Riley's connection to it, and that seven of the nine witnesses to the massacre have died, in each case when Karidian's troupe was somewhere nearby.