A Vulcan named Sybok, who embraces emotions rather than logic, gathers followers for a crusade on the desert planet Nimbus III and occupies the planet capital, "Paradise City". Among his hostages are the three ambassadors of the Federation, the Klingons and the Romulans. When a barely operational Enterprise-A comes to the rescue, Sybok seizes control of the ship too. Spock has to confess to Kirk that the rogue Vulcan is his half-brother. With his telepathic abilities Sybok influences the crew except for Kirk, Spock and McCoy to head for the center of the galaxy where he believes to find the mystical planet Sha-Ka-Ree. At their arrival the landing party is received by an eccentric being that claims to be "God" and demands to be brought aboard the starship to be able to spread his "wisdom". Sybok dies when he mind-melds with the creature to save the rest of the landing party. With help from the Klingons, "God" is eventually destroyed.