Nobody saw anything

Sive is standing on a crowded London Underground platform. When the train arrives, her two little girls, one aged six
and the other two, get on the carriage ahead of her. Because Sive is looking at her phone to see who is calling, she doesn't manage to get on behind them before the doors close. The train pulls away, leaving Sive standing on the platform.
By the time she gets to the next stop, she’s convinced herself that everything will be fine. But she soon starts to panic, because it’s not two children waiting for her on the platform, but just one. Is her other daughter lost? Hasa passer-by abducted her? Or is the culprit closer than she thinks? No one is telling the truth, everyone is lying, and the longer the search takes, the harder it will be to find her daughter…
The book is inspired by an experience from the author's own life. When she was twelve, she and one of her three sisters got stuck on a departing tube train while their parents and other sisters were left on the platform.