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.

Someone is to blame. Has your other daughter got lost? Been taken by a passing stranger? Or perhaps the culprit is closer to home than you think?