E Nelson Bridwell returns to script the story in Adventure 356 (May 67). Curt Swan’s art is the best thing about it. The story isn’t awful, just nothing particularly special, although it does establish a few things about the Legionnaires and their universe.
It’s Family Day, and all the Legionnaires with parents go off to celebrate, leaving Superboy, Mon-El, Brainiac 5, Element Lad and Dream Girl to hold the fort. Superboy`s and Element Lad`s origins make it obvious that they are orphans, and though it hadn`t been clearly stated about Mon-El, the fact that he spent a thousand years in the Phantom Zone makes it a bit of a given as well. Brainiac 5`s descent from Brainiac had never been made completely clear, but this is the first time we hear of him being an orphan. Similarly, this is new news about Dream Girl.
They get called to the planet Zinth to investigate a stolen power crystal, but their attempts to retrieve it from a deep lake wind up reducing them all to infants. Dream Girl warns Superboy and Mon-El that they would be vulnerable to this, but they arrogantly ignore her.
They get adopted, while Brainiac 5, whose intellect has not diminished with his age, finds a cure.
It turns out this was all a plot by the adoptive parents, who had lost their children earlier and wanted super-babies. Not only are the Legionnaires in no way upset by this, Dream Girl even gives it all a happy ending, forecasting that they will have new children by the end of the year.
The most significant thing is the mention of two planets, Yod and Rokyn. Brainiac 5`s homeworld is always called Colu, but in this story it`s called Yod. Later continuity would clear this up, giving it as an alternate name for the world, presumably from a different dialect. The Rokyn reference is more significant, as the story states that this is the name the Kandorians gave to the planet on which their bottle city was enlarged, the first indication of that event, which came to pass in the late 70s.