Night falls on Halloween eve, the museum in King's Lynn is preparing for an unusual event - the opening of a coffin excavated from the site of a medieval church. But when archaeologist Dr Ruth Galloway arrives to supervise, she finds the museum's curator lying dead beside it.

Ruth and Detective Inspector Nelson are forced to cross paths once again when he's called in to investigate the murder, and their past tensions are reignited. And as Ruth becomes further embroiled in the case, she must decide where her loyalties lie - a choice that her very survival depends on.