In an alternate world where nobody won WWII, three brothers are the only boys left in an orphanage whose dark secret is the reason for their existence—and the key to their survival—from the acclaimed author of Pet.

After a very different outcome to WWII than the one history recorded, 1979 England is a country ruled by a government whose aims have sinister underpinnings and alliances. In the Hampshire countryside, 13-year-old triplets Vincent, Lawrence and William are the last remaining residents at the Captain Scott Home for Boys, where every day they must take medicine to protect themselves from a mysterious illness to which many of their friends have succumbed. The lucky ones who recover are allowed to move to Margate, a seaside resort of mythical proportions.

In nearby Exeter, 13-year-old Nancy lives a secluded life with her parents, who dote on her but never let her leave the house. As the triplets' lives begin to intersect with Nancy’s, bringing to light a horrifying truth about their origins and their likely fate, the children must unite to escape – and survive.