Thirty years ago, Roger Heldman, notorious in the locality as a womaniser, died one night at the site of an archaeological dig on the ancient mound of Midsomer Barrow on his land. Now his only legitimate child, Gareth Heldman, is killed by a violent blow from a Celtic spear that was taken from the mound's central chamber. Local antiquities author David Hartley-Reade, who is widely known to be an illegitimate son of Heldman's, asks his widow for permission to hold a midsummer ceremony on the mound, invoking the possibility of an inheritance claim on the land to persuade her. As the reasons for wanting to hold the ceremony start to be realised, he is shot in the back with an arrow in front of the large crowd gathered there. Barnaby and Scott's investigation stirs up a maze of twisted relationships, professional jealousies and lies festering within the picturesque village community, as they discover other illegitimate children of Heldman's.

Based on the novels by Caroline Graham. Features: Midsomer map, cast filmographies, Caroline Graham biography.