Maxwell is living his worst nightmare when he begins to question whether his fiancée Imogen is his own blood sister separated by adoption. A visit to Imogen's birthplace in Cambridge stirs up déjà vu that intensifies his fears. While Detective Chief Inspector Morris Keene languishes at home struggling with a debilitating injury and post-traumatic stress his former partner Detective Inspector Chloe Frohmann is following a suicide case in which Morris' daughter Dora is suspected of assisting the death. When buried skeletons are discovered next to an old barn the suicide is linked back to Imogen's childhood revealing horrors of the past and new dangers in the present.