When builders renovating a café in King's Lynn find a human skeleton behind a wall, they call for DCI Harry Nelson and Dr Ruth Galloway, Head of Archaeology at the nearby University of North Norfolk. The bones are identified as the remains of Emily Pickering, a young archaeology student who went missing in the 1990s. Emily attended a course run by her Cambridge tutor. Suspicion falls on him and also on another course member - Ruth's friend Cathbad, who is still frail following his near death from Covid. Just when the team seem to be making progress, Cathbad disappears. The race is on - first to find Cathbad and then to exonerate him.