A gorilla is enchanted by Mrs. Howell's perfume and kidnaps her. After Gilligan accidentally spills the perfume all over his shirt, the gorilla decides to release Mrs. Howell and exchange prisoners.

The Castaways are frightened as the sounds of battle, including hand grenades and machine guns, rock the island. The culprit turns out to be a gorilla who has found an old WWII weapons cache.

An loin-cloth clad ape-man (Tongo) comes to the island, and makes off with their food and supplies. Actually, he is an out of work actor, who tries to convince the Castaways that he is a real uncivilized ape-man while studying for an upcoming role. After he cowers when confronted by a ""real"" gorilla, he leaves the island and the Castaways behind.

The Professor sees the arrival of a homing pigeon on the island as an opportunity to be rescued, and immediately begins to feed it a special diet designed to strengthen it so that it can fly again. In an attempt to speed the recovery time, the other Castaways also feed the pigeon, causing it to become too fat to fly. The pigeon is also trapped for a short while in a cave by a ""deadly six-foot black morning spider.""