Blackmail, revenge and, of course, murder strike again in Midsomer. Barnaby has plenty of suspects with motives but no real proof. For once his investigations take him beyond the confines of Midsomer, with trips to the seaside -- where he even takes time out for a paddle. The real evidence, however, rests much closer to home as Joyce and Cully discover. Guest star: Julia McKenzie (Agatha Christie's Marple).