The starship Enterprise finds the SS Botany Bay carrying humans from the 21st Century. Spock is fascinated by Ruth, who was dipped in Venus fluid moments after her birth. Ship historian Lt. Marla McGivers becomes entranced by Kahn, who plans to use her to take over the ship. A Vulcan female called Chandra, who just happens to be suffering from Pon Far, beams aboard to warn Kirk about Kahn and 'the Craving'. Indeed, Kahn releases the PSI2000 virus into the ships ventilation system which brightens everyones pupils. Dr. McCoy concludes that the only antidote is to have a powerful orgasm as soon as possible.