No one is more surprised than young Caitlin Maggert when she wakes up to her cat Rio talking to her and the world around them suddenly cloaked in grays. But when they team up with Caitlin's best friends to investigate the odd phenomenon, they discover a much larger sinister plan underway...and it's up to them to stop it, before it's too late.

Rio, Caitlin's Ragdoll cat with a panda face, has witnessed a very strange occurrence indeed. Asleep in Caitlin's beautiful pink bedroom-the envy of her best friend's Trudie and Molly-the beloved feline is awoken by a silver light which sucks up all the color out of the room and also results in Rio having the ability to talk, control the minds of suggestible humans-otherwise known as "cat people"-and telekinesis, able to move things with his thoughts.

Caitlin is shocked when everything around her-the blue sky, the green lawns, even her yellow school bus-is suddenly void of all color. After a bit of disbelief and quarreling, Caitlin finally convinces her friends of the unusual events. The three girls, along with Rio, have a sleepover at Caitlin's where they discuss their investigative plan to get to the bottom of the cause of this new dull and gray world.

The friends track a trail of drops of yellow color to an abandoned building where, inside, they find a scientific lab with computer monitors and a large cauldron-like device, swirling with colors. They soon learn that a world-famous scientist, Professor Pinch, believing he was hired to perform research that would change the world for good, was actually duped by a criminal mastermind, MacDougal, to create a destructive device that would be disastrous for the world.

Caitlin, Trudie, Molly, and Rio are the only ones who know about this evil plan and they, along with the kindly professor, must stop MacDougal before the invention is used against the world. Can they restore the colors and stop the brute before it's too late?