Alison is more alone than she's ever been. She is convinced that her ex-husband Jack is following her. She is certain she recognizes the strange woman who keeps approaching her in the canteen.

She knows she has a good reason to be afraid. She just can't remember why.

Then the mention of one name turns her life upside down.

Alison feels like she's losing her mind . . . but it could just lead her to the truth.