World War II has been raging for less than a year. All Grey Davis has ever wanted was to join the Navy and help Britain win the war, same as his older brother George, who is a member of the British Expeditionary Forces. There's just one problem: Grey is only twelve years old.

When Grey is evacuated to the English countryside to avoid the nightly air raids, he takes off on his own and lies his way into the Navy. Although the other soldiers quickly figure out he has no business being onboard a Navy ship, Grey soon proves his worth, earning the friendship and loyalty of his crewmates, while their captain remains none the wiser.

When word comes that the Allied soldiers fighting in Dunkirk are in trouble, George among them, Grey is desperate to join the rescue effort. But after his captain discovers his true identity and sends him back home, Grey has no choice but to steal his stepfather's boat and set off on his own for Dunkirk.

Except, not completely on his own: Grey has accidentally stolen the boat with his stepfather onboard.

Desperate, afraid, and determined to find his brother, Grey must persuade his stepfather that, together, they can aid in the rescue effort, face the enemy in strange waters, and survive a devastating battle, if he's to have any hope of bringing his brother home.

From beloved #1 New York Times bestselling author Jennifer A. Nielsen comes a thrilling, twisty story, set against the dramatic backdrop of the fighting and rescue effort at Dunkirk, about courage, sacrifice, and the lengths we will go to for the people we love.