Frank Hopkirk, an environmental adviser on the proposed site of a controversial Goodfare supermarket in Elverton-cum-Latterly, is found stabbed to death in an old farm building on the site. Barnaby & Jones question locals on both sides of the debate over the plans, and find that Mr Hopkirk had extra-curricular dealings with a number of the local ladies and their businesses. But which one of these caused passions to be stirred up to such a murderous extent?