Eddie Jessup egy tudóstársával együtt kutatja az emberi evolúció eredetét. Egy teória szerint az agy feltáratlan területei évmilliókra visszamenőleg megőrzik a genetikai fejlődés során végbement változások információit. Hosszú ideje nem jutnak eredményre, így Eddie egy indián törzs szárított gombájával drogozza be magát, ám a kísérlet kicsúszik az irányításuk alól. Ezt követően Eddie különös fizikai elváltozásokat észlel a testén.

A British scientist is discovered to have been passing information to the Communists, then kills himself. Another scientist decides that they might have brainwashed him by a sensory deprivation technique, but he doesn’t know if someone really can be convinced to act against their strongest feelings. So he agrees to be the subject in an experiment in which others will try to make him stop loving his wife.

An obsessive psychologist attempts to reprogramme her subconscious mind, but when her actions become increasingly uncharacteristic she fears her experiment is dangerously out of control.

Army Captain Edward Hall returns to the US after two years in a prison camp in the Korean War. In the camp he was brainwashed and helped the Chinese convince the other prisoners that they were fighting an unjust war. When he comes back he is charged for collaboration with the enemy. Where does loyalty end in a prison camp, when the camp is a living hell?

After his wife disappears a man uses a sensory deprivation tank to solve the mystery.