Synopsis: Superman brings his Fortress of Solitude to Metropolis for tours. His robots keep guard against possible saboteurs sneaking in. During the tour Superman relates the stories of when he located his Fortress in space and in the center of the Earth.
Two members of the Anti-Superman Gang plant an explosive bomb inside the Fortress that they smuggled in past the guards. Superman is warned by the citizens in Kandor of the bomb and is able to dispose of it before it can destroy the Fortress. Superman then rounds up the gang.
Synopsis: Supergirl finds a small piece of kryptonite which she takes to a laboratory. She experiments with chemicals in an attempt to find an antidote to kryptonite poisoning. She is unsuccessful and throws the piece into the woods to dispose of it.
Supergirl, as Linda, later befriends a stray cat. The cat is orange with white stripes, she names him Streaky. While playing in the woods, Streaky is exposed to the kryptonite fragment, now X-kryptonite. The radiation gives Streaky super powers. While learning to fly he smashes into a Superman doll and takes the cape.
Streaky flys around town, helping the other cats, and fights a dog. Supergirl hears Streaky and flys to check on him. She sees that Streaky is super now and plays with him. Streaky’s powers vanish suddenly. The effects of the radiation were only temporary, and Supergirl does not know what caused them.