Despite the promise on the cover of Action 266 (July 1960), neither the Superman nor Supergirl story in this issue pit the two teams against each other, although Krypto and Streaky do both appear in the Siegel and Mooney Supergirl tale.
Streaky, the Super-Cat is brought back in this story.
Paul Dexter, a boy at the orphanage, is central to this tale, but it’s his only appearance. Superman stops by, entertaining the kids, along with Krypto. Paul ties a cape on Streaky, and tries to coax him into being super-powered, which, of course, does not work.
But that piece of x-kryptonite is still around. Streaky gets it buried in a ball of twine, which stays in the basement of the orphanage, where it can power the cat up whenever the story requires it.
Paul sees Streaky’s super-deeds, but none of the other kids do. Linda rushes around covering up for Streaky, in case it reveals her identity, but this does make Paul look like he is either a compulsive liar, or insane.
In the end Supergirl arranges a preposterous explanation, that Krypto was trying to make Streaky think that he had powers. Oh, the way those animals pull human-like tricks on each other.