As a teenager, Tess falls into environmental activism - and the arms of an older, charismatic protester. She has never been happier. When he suddenly disappears, leaving her pregnant and alone, she is shattered. Slowly, though, she rebuilds a life for herself and her daughter Mia. "We're all we need," she sings to Mia as they dance around the kitchen. "Me and you, us two."

But, as Mia nears her thirteenth birthday, the death of a relative sparks questions - about activism, about her family, about her father - that Tess cannot answer. And when a hidden letter is found, Tess suddenly has urgent questions of her own. As mother and daughter pull apart, caught up in their own private quests for answers, the certainties of memory and history begin to unravel and a single shocking question emerges: if your past is all a lie, then who are you?

Complex, profound and devastatingly timely, this brilliant psychological suspense explores the twisted world of undercover operations, the most secretive part of the secret state where nothing is sacred and no one cares to count the cost.