Fox Street was a dead end. In Mo Wren's opinion, this was only one of many wonderful, distinguishing things about it.

Mo lives on Fox Street with her dad and little sister, the Wild Child. Their house is in the middle of the block—right where a heart would be, if the street were a person. Fox Street has everything: a piano player, a fix-it man, the city's best burrito makers, a woman who cuts Mo's hair just right, not to mention a certain boy who wants to teach her how to skateboard. There's even a mean, spooky old lady, if ringing doorbells and running away, or leaving dead mice in mailboxes, is your idea of fun. Summers are Mo's favorite time, because her best friend, Mercedes, comes to stay.

Most important, though, Fox Street is where all Mo's memories of her mother live. The idea of anything changing on Fox Street is unimaginable—until it isn't.

This is the story of one unforgettable summer—a summer of alarming letters, mysterious errands, and surprising revelations—and how a tuft of bright red fur gives Mo the courage she needs.