While driving home from a party in the village of Newton Magna, Dr. Burgess accidentally hits someone with his car. He goes to a nearby pub for assistance, but when they return to the scene of the accident, there's no one to be found. The pub owner seeks Tom Barnaby's assistance but all he and Sgt. Troy can find is a bloody handkerchief by the side of the road. Barnaby does meet up with Melvyn Stockard, now a buyer and seller of horses, but who was once convicted of robbery. They know that the person struck by the car was a recently arrived Irishman who claimed to be a horse whisperer. When a body is found in the village well, the police uncover a complex web of marital infidelities and deceit. When another villager is found murdered, Barnaby finds that the horse whisperers appearance in the village some weeks before may been for a very specific purpose.