The cover of Supergirl 5 (June 1973) bills Zatanna as appearing in the issue, but her story is just a reprint of her debut tale, from Hawkman 4.
So that leaves just the Supergirl tale, by Arnold Drake, John Rosenberger and Vince Colletta, to discuss. The art on this one feels a step up from Saaf, and though the story is not brilliant, at least it's not a romance. The tale begins as Linda Danvers receives a book written in something like Sanscrit. Shortly afterwards, she loses her powers. She meets up briefly with Superman, and then catches a ride with Linda's roommates to go to an amusement park.
At the park one of the roommates, Rowena, goes missing. While hunting for her Supergirl winds up pulled to another dimension. Rowena is being held captive there in order to force Supergirl to help the leader of that world. He had also sent her the book, which caused her powers to vanish, and now he restores them. His plan relied on Supergirl choosing to come to the park, which was an iffy proposition at best. Anyway, in his world, rebel students are causing a problem at the university. He demands Supergirl impersonate a goddess from their dimension and lead the students into an ambush.
She does so, but beforehand rigged Rowena's watch, which was shown to her as proof that the bad guy really had the girl. So once Rowena is let free Supergirl makes the watch blow up in the bad guy's face, and helps the students defeat him.