In Catalyst, award-winning authors Anne McCaffrey and Elizabeth Ann Scarborough introduced listeners to the beguiling Barque Cats: spacefaring felines who serve aboard starships as full-fledged members of the crew. Highly evolved, the cats share an almost telepathic bond with their minders, or Cat Persons - until, suddenly, there is no “almost” about it, and a particular Barque Cat, Chester, learns to ex- change thoughts with his human friend, Jubal. Other cats soon gain the same ability.

Behind the seeming miracle is a mysterious cat named Pshaw-Ra, who possesses knowledge and technology far beyond anything the Barque Cats - or their humans - have ever seen.

When fear of a virulent plague leads the government first to quarantine and then to kill all animals suspected of infection, Pshaw-Ra - with the help of Chester, Jubal, and the crew of the starship Ranzo - activates a “mousehole” in space that carries the refugees to a place of safety: Pshaw-Ra’s home planet of Mau, where godlike cats are worshiped by human slaves.

But Pshaw-Ra’s actions are less noble than they appear. The scheming cat plans to mate the Barque Cats with his own feline stock, creating a hybrid race of superior cats - a race destined to conquer the universe.

Yet right from the start, his plans go awry. For one thing, there’s a new queen on Mau: Pshaw-Ra’s daughter Nefure, a spoiled brat - er, cat - with a temper as short as her attention span. Pshaw-Ra’s other daughter, the rightful queen Renpet, is exiled, running for her life in the only direction available to her — down into the vast catacombs beneath the Mauan desert. Far from receiving the hero’s welcome he expected, Pshaw-Ra must use every bit of his considerable cleverness just to survive.