Among the Lotus Eaters

Evidence of a Starfleet emblem on Rigel VII suggests that Pike's disastrous earlier visit there broke the Prime Directive. Pike, La'An and M'Benga beam down and learn that radiation from nearby asteroids wipes people's memories. Zac Nguyen, a crewman presumed dead after the first mission, has made himself ruler, enforcing a caste system in which labourers forget everything each day. The away team soon lose their own memories and are put to work. In orbit, the radiation also affects the Enterprise crew, and Ortegas, guided by the ship's computer, rediscovers who she is and flies the ship clear of the asteroids. Pike fights his way into Nguyen's castle, whose walls shield against the radiation, and defeats him. With their memories back, the crew destroy the main asteroid, restoring the memories of the planet's people, though some, like Luq, recover painful ones.