One of them has killed before. One of them will kill again. In the sweltering summer of 1997, straight-laced, straight-A student Karen met Biba - a bohemian and impossibly glamorous aspiring actress. A few months later, two people were dead and another had been sent to prison. Having stood by Rex as he served his sentence, Karen is now married to him with a daughter, Alice, who runs a vintage clothing company in London. They're a normal family, as long as they don't talk about the past, never mention the name Biba, and ignore Alice's flashes of dark, dangerous fury. Karen has kept what really happened that summer of '97 hidden deep inside her. Alice is keeping secrets of her own. But when anonymous notes begin to arrive at Alice's shop, it seems the past is about to catch up with them all ...