Rhiow seems a perfectly ordinary New York City cat. Or so her humans think—but she is much more than she appears. With her partners Saash and Urruah, she collaborates with human wizards to protect the earth from dark forces and maintain the network of magical gateways that connect to different realities. But amid this amazing secret animal world lies a danger that threatens not only the cats of the world, but humans as well.

Traveling back in time to 1874 London to prevent an assassination plot against Queen Victoria, the feline wizards of Grand Central Station—leader Rhiow and her able partners Urrah and Arhu—must summon their powers to avert disaster in Victorian England, or else their archenemy, the evil Lone One, will warp time and trigger Armageddon. Teamed with a young Arthur Conan Doyle, Queen Victoria herself, and other historical figures, the feline wizards set out to find the forgotten magic that will rewrite history—or the cats who can save mankind will never have existed.

Life's already much too busy for Rhiow and the other cats of the New York City worldgating maintenance teams. The old, cramped Penn Station is being torn apart and relocated into its big new building, which means that the Penn worldgates have had to be moved too. Everyone's nerves are in shreds, and no one's had enough sleep for a human, let alone a Person. So when Rhiow goes staggering home to her litterbox the morning after the job's done and finds it already occupied by another cat—who then vanishes—at first she thinks she's hallucinating. But she's not. When her team is called to Los Angeles to do a minor consult after the city's single worldgate is deranged by a string of earthquakes, Rhiow's "hallucination" reappears bearing a dire message from the past. The messenger, a tom called Hwaith, reveals that similar earthquakes are striking Los Angeles in 1946 — indicators not only of increasing instability in the San Andreas Fault, but of something far more troubling. Something is trying to subvert the Los Angeles gate to its own purposes. "The Lone Power?" Rhiow asks. "No," Hwaith says. "Something worse. Something from outside." Rhiow and her team find themselves caught up in ever-deepening peril and mystery as they make the dangerous trip back to post-war Los Angeles. Their intervention plunges them headfirst into the glitzy, murky world of 1946 Hollywood, a smoggy film-noir landscape filled with glamourous starlets, flamboyantly corrupt studio heads, wicked, pampered cats with hidden agendas, unsolved murders, snoopy screenwriters, scheming PR flacks, and a shadowy, celebrity-ridden cult dabbling in knowledge better left alone—knowledge which could destroy their world's present and doom its future, if the dreadful promise of the Year of the Black Jaguar is fulfilled...