Who is watching Nell Masters?

Nell Masters is certain someone is following her. The hairs on the back of her neck rise when she travels to and from work, there are silent calls to her office, and a huge bouquet of flowers arrives without a card. And Nell has a reason to be looking over her shoulder, because she has a secret that shes hiding from everyone in her life, including her new partner, Alex. But Alex also has secrets of his own.

Fourteen years earlier, when Nell went by the name Elle Nugent, she witnessed a student, Bryony Sanders, getting into a strangers car. When Bryony was found murdered, Elle became obsessed with finding the person responsible. She was convinced she knew who it was and her fixation with Brett Parker, the man she accused, led her down a dangerous path

Now, Nell tries to convince herself that this unnerving feeling of being watched is all in her mind. Has someone from her past discovered her new identity? Has the stalker become the stalked? Or is there something even more deadly at play?