From the author of I, Cosmo comes a humor-filled, heart-tugging tale of a genius mouse, secretly freed from a lab, who’s in search of a real home—and a way to free her old friends.

Clementine is different from other mice: she can calculate the speed of light and she dreams in Latin. The scientists say she’s a genius and put her through test after test. Clementine is proud of being a good lab mouse, but she’s lonely. Her only snatches of friendship occur during her late-night visits with a chimpanzee named Rosie. When a compassionate lab technician frees Clementine, the mouse discovers an outside world full of wonders: Brussels sprouts, games of speed chess, television fame, and a chance for a real home. But for Clementine, it’s not enough to be free when she knows that Rosie and the other mice are not. This tender, lively adventure story, narrated in letters from a mouse to a chimpanzee, shows us that goodness is something we have to define for ourselves—and that courage and wisdom aren’t proportionate to size.