The Enterprise is ordered to pursue a group of anti-establishment idealists who have stolen a space cruiser and made off for the mythical planet Eden. When the group pushes their stolen ship beyond its limits, the Enterprise is forced to rescue them by transporting them aboard. This merry band of space-hippies includes an insane leader (Dr. Sevrin), an academy drop-out and former love interest of Chekov (Irina), and the son of a Catullan ambassador (Tongo Rad). With the Federation undergoing fragile treaty negotiations with the Catullans, Kirk is ordered by Starfleet to treat the dissidents with "extreme tolerance." Kirk finds the group and its leader too difficult to deal with while Spock maintains a deep curiosity about their ideals. Kirk appoints Spock as liaison for the group during their stay on the Enterprise. Dr. Sevrin demands to be taken to Eden, but Kirk refuses on the grounds that his orders from Starfleet dictate that the group be taken to the nearest star base.