Ghosts from the past have the nasty habit of refusing to stay buried.

Returning from an extended stay in Scotland, life for Mikaela and Brodie picks up right back where it left off. Brodie is immediately tasked with a new case for the Agency, while Mikaela must attend a reception for the release of her latest novel. But, as it always does, intrigue has begun to creep its way back in.

While at the reception, Mikaela encounters a mysterious woman who bares a striking resemblance to her. But, before she can ask any questions, the woman disappears.

Days later Mikaela's sister Lenore sees the same woman, raising more questions and bringing back painful memories. The woman claims to be a long-lost half sister, with old letters and documents that seem to support her claim. And there is that undeniable resemblance.

But is she who she claims to be?

Mikaela sets out to investigate, drawing Brodie in to support her even as he cautions that the woman might be telling the truth.

Their search takes them into the past as old secrets come to light, from a private hospital in the south of France to a grave in Highgate Cemetery, desperate to expose the truth.

But as they both know only too well, awaking old ghosts can be deadly...