30 years ago, archaeologist Paul Heartley-Reade claimed to have found a Celtic spear and chalice in Midsomer Barrow. The relics vanished and there has over the years been extensive debate in academic circles about the find. When the spear is used to kill Gareth Heldman, Barnaby and Sgt. Scott find themselves investigating several local villagers including Harry Green who was fed up with Gareth's advances toward his girlfriend, Vanessa Stone. Vanessa herself had a disagreement with Gareth when he threatened to pull out of a business deal. When a second murder is committed, the police start to unravel a complex web of interrelationships among virtually all of the suspects.