Caro lives at the Cherry Hill Orphanage, where she is a quiet role model for other kids, and a favorite of orphanage director Mrs. George. Mary Mouse, living behind the orphanage walls, is her community’s art thief (the art being postage stamps). On one of her forays into Mrs. George’s office to steal stamps, Mary is almost caught by the cat until Caro intervenes, and a bond develops between mouse and girl. It soon becomes clear to Mary Mouse that Mrs. George is running an illegal adoption ring. Caro is beginning to grow suspicious, too, but finds it hard to believe Mrs. George would do something wrong. Her best friend, Jimmy, thinks otherwise. When the new baby Caro had been helping care for suddenly disappears, Mary and rogue mouse Andrew try to help gather evidence while Caro and Jimmy do the same. An animal fantasy full of humor and heroics also has a slight edge that makes it more suited to an older audience than the cover might suggest, at least as a read-aloud. And while Martha Freeman’s characters can be labeled “good” and “bad,” they are drawn with refreshing complexity. (Ages 8–10)