Superman

Clark takes a working vacation in Hollywood. He saves a famous actress, Dolores Winters, from an attempted assassination, and she promises him an interview the next day. When he arrives for the interview, though, she coldly refuses him. Later, she announces that she's retiring from film, and holds a huge party on a boat to celebrate. With all the wealthy and famous people aboard, she moves the boat out to sea, kidnapping them and holding them for ransom. It ultimately transpires that Ultra was not so dead as he had seemed, and his assistants kidnapped the actress and transferred his brain into her body. Superman rescues everyone, but Ultra-in-Dolores's-body escapes.

Incidentally, as usual, the cover of this comic has nothing to do with the story inside--Superman doesn't tear the door off any vaults in this one.

Zatara and the Moon Men

A strange mist has begun collecting along shorelines in Africa and Europe--a deadly mist. Thousands have died, and the "great powers of the world" decide to call in Zatara, who has "saved the world from an icy death some months ago". Could they be referring to the events of Action Comics #15? That one had to do with melting ice, though...

Anyway, they send for Zatara. He decides to sleep on the problem, but is awakened and chased from his bed by mist that very night. He determines that it must be "a gaseous form of radium [that] causes those burns and choking". Then he's visited by a woman, Nala, with fairy wings, who claims to be from the Moon--well, descended from people who came from the moon, or something. He follows her to a secret cave, where dwell moon men--strange creatures, bent on the destruction of all life on Earth. They have created a gaseous form a radium, and intend to release it in short order. Zatara does his thing and arranges for the gas to be released inside their city, followed by deadly snakes (moon-snakes?), ensuring that every last moon man is dead.

Finally, Nala explains to Zatara that her people are "a race that inhabited the Earth a million years ago" and now live on the Moon. She invites him to come up to the moon with her--next issue!