Mr. Mxyzptlk is back in this dimension for his regular visit, and he hasn't come alone! He's not here to cause the usual mischief and mayhem this time--his new puppy, Bxtr, does enough for both of them! Mxy's in serious need of some obedience training, and so he's come to Highland Canine Training in Harmony, NC, hoping that they can tame his magical mutt. Though the trainers at the school may be top-notch, housebreaking an omnipotent puppy is no job for mere mortals. They're going to need a consult, someone who has experience dealing with super-powered pooches, someone with the power and cunning to deal with whatever a god-dog can throw at them. Yes, training this puppy is a job...for Superman and Krypto!
And in the last installment of the Krypto Second Feature, the Mutt of Might is summoned to the Kennel of Solitude, along with his counterparts from across space and time! A great malevolence threatens to wipe out all of their masters, and only the Infinite Legion of Super-Pets can stop it!