Back onboard the "Enterprise", the four meet with Chief Engineer Scott to consider Sargon's request, and Kirk convinces the others with a rousing speech about risk. The spheres of Sargon, his wife Thalassa, and his former enemy Henoch, are brought up from the planet. McCoy supervises as Sargon takes Kirk's body again, and Thalassa and Henoch take Mulhall's and Spock's bodies, respectively. When Sargon and Thalassa become exhausted by the strain of the transference, Henoch instructs Nurse Chapel in preparing a serum that will strengthen the host bodies. Chapel notices that the serum in the hypospray designated for Kirk does not contain the correct formula. Henoch confesses that he intends to kill Kirk, and Sargon with him, in order to keep Spock's body. Henoch then erases Chapel's memory of the conversation.