It's summer when Elm Hill lido opens, having stood empty for years. For Natalie Steele, it offers freedom and leads her to Lara Channing, a charismatic former actress, who seems all too happy to invite Natalie into her elite circle. Soon Natalie is spending long days at the pool, basking in popularity. But is it too good to be true? Why are dark memories of a summer long ago now threatening to surface? Could Natalie have been swept dangerously out of her depth?