Police constable Hamish Macbeth is baffled by two apparently unrelated mysteries: a huge quantity of table salt has been stolen from Rory Campbell's general store; and Geordie Robb, a local bully, is missing. Hamish outwits his superiors when he makes a connection between the two mysteries.

Newcomers to Lochdubh Vicky and Paul Jeffreys cause a stir: Vicky tries to put reluctant villagers back in touch with their Highland heritage, gradually alienating them. Hamish investigates when this unpopular, meddling newcomer, receives anonymous threats.

Major Maclean stages a robbery to make a false insurance claim. Before Hamish can settle things quietly, Inspector Bruce instigates a major surveillance operation.

On a mountain trek led by Colonel Don Maxwell, Hamish advises caution once the climbers have reached their goal, but Maxwell urges them on into a dangerous situation.

A hellfire sect leader sees the town as the new Gomorrah. Hamish's reputation is undermined and his tolerance stretched to the limit when he is denounced as the devil incarnate.

Village reporter Isobel stumbles on a story that could put her in the big league. She emerges with a fresh image and a hot new boyfriend, leaving Hamish squirming with jealousy.

Hamish turns a deaf ear to the local pirate radio station which is having a remarkable influence on the town. But when the radio authority sends a defector van to close down transmission, he is caught up in a conflict of loyalties.