Eliza has lived two lives – one before she fell into an obsessive teenage friendship with Eric and Maggie, and the one after it was destroyed in a single afternoon. To Eliza, Eric and Maggie were irreplaceable, so she hasn’t. Instead, drifting through life alone, she spends every morning diving into her memories as she swims in Hampstead Ponds, her guilt never far below the surface. Twenty years might have passed, yet Eliza still can’t help searching for Maggie everywhere. Then one day she spots a woman who looks just like her. Eliza has spent half her life wondering what really happened that afternoon and if Maggie’s back, will it help her finally get answers? But memories are like ripples on water, and can be deceptive. As the past and present collide, Eliza begins to wonder: will learning the truth set her free – or will it only drag her down deeper?