A man falls overboard from a ship arriving in the estuary near Hull. He is washed ashore dead. Because of injuries sustained in the water he is unrecognisable. It's amazing how a single situation like this can lead on to the most complex crimes. The most careful planning can go awry so easily, and only an expert can interpret the facts with which he is presented. Guest stars Barry Creyton, Harold Goodwin, Peter Madden, Michael Brennan, Alan Tilvern, Tony Caunter, Reg Pritchard and Brian Badcoe.