London, 1985. Joe, father to 11-year-old Matty, has disappeared and nobody will explain where he's gone, or why. In the long, hot summer that follows, Matty's hunt for Joe leads to the ponds at Hampstead Heath. Beneath the water, there is a new kind of freedom. Above the water, a welcoming community of men offer refuge from an increasingly rocky home life. Fourteen years later, a new revelation sees Matty set off alone in a campervan, driving westwards...