Wormwood Scrubs playground, 1980. The wind blows across the common, and the girl in her shorts shivers. The playground is isolated, timeless. Far from the prying eyes of grown-ups, she and her friends can play make-believe here. The looming slide is a mountain; the upturned log a pirate ship. But six-year-old Sarah Ferris does not know that in two days' time, she will be dead: a victim of jealousy, betrayal, and her own innocence. Hammersmith, 2019. Cleaner Stella Darnell loves rooting into shadowy places and restoring order. She'll clear your attic, polish your kitchen and scrub your bath--but she also investigates cold cases. Stella can spend hours sifting through forgotten evidence looking for shreds of evidence the police might have missed. So when a woman is found dead, and the killer is linked to the Sarah Ferris murder, Stella is the woman for the case. But dredging up the past can be dangerous--especially if the playground killer is back.