On the hottest day of the summer, we wait for Molly on the riverbank, desperate to slip into the cool water. But as the sun starts to fade, it's clear she isn't coming. We'll never see our friend again...

Years later, after an unexpected inheritance, Briony returns to her godmother's grand countryside home where she spent her teenage years. Despite its idyllic appearance, the old stone house carries memories Briony would rather forget. To escape the controlling behaviour of her godmother's son, Jeremy, Briony spent every possible moment with her best friends, Molly and Samantha, until the day Molly vanished without a trace.

Briony is certain Molly was keeping a secret in those final days. Why else was she acting so strangely? And why did Briony constantly feel like they were being watched? When Briony discovers Molly's decades-old bathing suit in a locked part of the house, she begins to piece together what happened to her friend. But, as more skeletons come to light, is Briony ready to uncover the truth after so many years?