The residents of Elverton-cum-Latterly are bitterly divided by plans by supermarket giant Goodfare to open a store in the village, supported by trendy vicar Rev Suze.

Before a protest meeting, rural pursuits organisers Celia and Jeremy Patchett and glamorous widow Rose Southerly gather at the house of Orlando and Ginny Lamington. The friends pledge their loyalty to "the business", although all three women had mysterious meetings with moustachioed businessman Frank Hopkirk.

Rose's privately-educated daughter Dora and Otis, son of publican Danny Piggott, sneak out of the hall for cigarettes and vodka, while shopkeeper Gary Talbot accuses Danny of selling out to Goodfare and a scuffle breaks out. Then Otis and Dora discover the stabbed body of Frank Hopkirk at Jubb's Timber Yard.

Otis admits he saw Frank earlier, digging in Jubb's Field. His briefcase contains a business card for Rose's cookery school and one of her knives - the murder weapon. Rose tells the police she was giving him private cookery lessons.

Frank worked as a consultant for Goodfare and bruising on his body suggests he was beaten for pleasure. Barnaby and Jones learn he was looking for a man called Johnny who once worked at the mill.

The detectives confront Rose and she admits indulging in role play as a fantasy wife for money, recording it all on CCTV. But the tape reveals Frank left her at lunchtime alive and well - someone is trying to incriminate Rose.

According to the council, Goodfare was getting the land cheaply in exchange for cleaning up pollution and building amenities. Dr Bullard discovers Frank had a stroke before he died and was paralysed while being stabbed. He also had saddle soap under his fingernails and had recently fired a shotgun.

Barnaby goes to the rural pursuits centre to find Celia being "rescued" from a mantrap, covertly filmed by Jeremy. The couple admit they gave Frank a "shooting" session, and Ginny also admits she took him "riding".

Jones finds Johnny but gets hit on the head when he disturbs a fight. Otis and Dora claim Rev Suze is involved with Gary Talbot. Who is framing Rose and what's the truth behind the tangled friendships, village affairs and sexual role play? Barnaby and Jones must discover what is really polluting Elverton.