Ellen Shaw arrives in London expecting to join her sister Fiona, who's found her the perfect job managing an antiquarian bookshop. Instead, she finds an empty apartment, and no sign of her sister. The only contact Ellen has is Hugh Weston, Fiona's boss and the bookshop's owner. Though Hugh seems solid and dependable. He remains a stranger she's not sure she can trust.

Hugh has his own theories about Fiona's disappearance. His Grandmother had been murdered only days before, and Hugh suspects Fiona had something to do with it. Is Ellen simply an innocent woman looking for her sister . . . or a partner in the crime, too?

But as danger begins to stalk Ellen through the streets of London, Hugh has only moments to decide if she's capable of murder. . . or if she's simply an unlucky pawn who desperately needs his help.