There has been a Pon Farr outbreak on New Vulcan. Sarek goes to investigate but is trapped on an uninhabited planet with Winona Kirk just as he begins Pon Farr himself. Spock and Jim save their parents, only to discover that they are now stepbrothers. Dealing with the outbreak, their parents' new relationship, and their own friends-with-benefits relationship will challenge both of them.

Spock is still in a relationship with Uhura when he has his first Pon Farr. Kirk diverts the Enterprise to New Vulcan so Spock can marry T'Pring, who survived Vulcan's destruction. However, when he gets there, he finds his wedding doesn't go according to plan.