Two sisters abandoned

It was a treat, she said. An adventure. A train journey to the mainland. Six-year-old Lara Arden and her older sister Georgia happily fill in their colouring books as their mum pops to the buffet in search of crisps. She never returns. Two little girls abandoned. Alone.

Present day

Twenty years later, and Lara is now a detective inspector on her native Isle of Wight, still searching for answers to her mother's disappearance.

A call comes in. A small child, a boy, has been left abandoned on a train. Like Lara, he has no relatives to look after him. It feels as if history is being repeated - but surely this is a coincidence?

A series of murders

Before Lara can focus on the boy's plight, she's faced with a series of murders. They feature different victims in very different circumstances, but they all have one thing in common: they all leave children - alone - behind.

So who is targeting Lara? What do these abandoned souls have in common? And how does this connect to the mystery of Lara's missing mother?