From #1 New York Times bestselling Sisterhood of the Traveling Pants author Ann Brashares and her brother Ben Brashares comes the first book in a "pulse-pounding" (Publishers Weekly, starred review) middle grade alternate history thriller trilogy that asks what it would be like in present-day America if Germany had won World War II.

Henry, Frances, and Lukas are neighbors, and they used to be best friends. But in middle school Frances got emo, Lukas went to private school, and Henry just felt left behind. When they come together again for the funeral of a pet gerbil, the three ex-friends make a mind-blowing discovery: a radio, buried in Henry's backyard, that allows them to talk to another group of kids in the same town...in the same backyard...eighty years in the past.

The kids in 1944 want to know about the future: Are there laser guns? Flying cars? Jetpacks, at least? Most of all, they want to know about the outcome of the world war their dad and brothers are fighting in. Though Henry is cautious--he's seen movies about what happens when you disrupt the fabric of time--soon the present-day kids are sending their new friends on a mission to rescue a doomed candy store. What harm could that do? But one change leads to another, and when the six friends alter history in the biggest way possible, it's up to them to change it back.