Deep in Blacktrees Forest is a bombproof shelter built by a man named Warren Kaine. His extreme paranoia has drawn other survivalists to the village, and now a doomsday prepper group meets weekly.

Gated estate Challis Court is a tight-knit community for retired police officers, but when a new arrival is found dead, the other residents regard the murder as an affront; Barnaby realizes that the killer is likely an ex-police officer.

A trendy organic bakery in a restored mill is causing resentment amongst several villagers. Causton CID don't take the complaints too seriously until several people are dosed with a dangerous hallucinogenic. Then the first death occurs.

Parish chairwoman Lois Springfield is found dead in a local theatre. The detectives assume it's because of her hostility toward a drag show being organised, but other motives are at play.