No one saw it happen.

Your two little girls jump on the train ahead of you. As you try to join them, the doors slide shut and the train moves away, leaving you behind.

Everyone is lying.

It's only when you reach the next stop that you truly begin to panic. Because there aren't two children waiting for you on the platform. There's only one.

Your nine-year-old son says there’s a man living in the attic.You keep hearing noises up there when you’re all alone, but when you check, the loft space is empty.And then your daughter shows you something on her phone – a video of a man walking around inside your house while no one is home – and you start to panic....

Close your eyes.

The game of hide and seek is over, but little Lily Murphy hasn't been found. Her parents try to stay positive, but they know this peaceful Dublin suburb will never be the same again.

Count to ten.

Years later, Joanna moves into a new house. It seems perfect in every way, until she learns that Lily Murphy used to live here....

Marissa Irvine arrives at 14 Tudor Grove, expecting to pick up her young son Milo from his first playdate with a boy at his new school. But the woman who answers the door isn't a mother she recognises. She isn't the nanny. She doesn't have Milo. And so begins every parent's worst nightmare....