When a sixth form student who is spying on his French teacher becomes the prime witness to her husband's murder, DCI Taggart, newly promoted DC Jackie Reid and DS Jardine have no choice but to exhume an entire graveyard when the prime suspect - an undertaker - refuses to let on where he has buried the parts of his mutilated body. Unfortunately, one of the deceased includes Jean Taggart's Aunt Hettie (much despised by Jim) - who also passes away in the episode and inconveniently interred by the same undertaker.

The discovery of two skulls at the site for a new by-pass road leads the team to a pharmaceutical company. Someone doesn't want the skulls identified and will go to any length including murder.