Supergirl builds herself a secret Fortress of Solitude, but it is found by explorers who use the information to blackmail Supergirl into making them rich.; Supergirl is invited to the 30th century to join the Legion, but is rejected because Red Kryptonite has aged her beyond the limit for Legionnaires.; Supergirl encounters Comet for the first time.; Supergirl is called upon by Lori Lemaris to help Atlantis from a disaster. There, she falls in love with a merboy, Jerro.; Supergirl recovers a small Kryptonite meteor and unsuccessfully tries to find a chemical way to render it harmless. Later, Linda saves a stray orange cat from a dog. The cat follows her to the orphanage where Linda is given permission to keep him. Because of the white markings on his side, she calls him Streaky. Streaky discovers the piece of discarded Kryptonite, and receives super-powers from it. Streaky feeds some stray cats by tipping over a milk truck and chases off a bullying dog. Eventually his "meows" attract Supergirl and the two have some super-fun before Streaky's powers fade away.; Supergirl goes back into the past to meet Superboy, so he can have a super playmate.; Superman spies a crashing rocket and discovers his cousin Supergirl. She tells him how Argo City survived the destruction of Krypton and how her father sent her to Earth when the inhabitants of Argo City were threatened by Kryptonite poisoning. Superman sets her up in Midvale Orphanage so she can adjust to life on Earth.; Supergirl visits the stone age so that she can practice using her powers openly.; Superman introduces his super-powered cousin to the world.