Three guests at Martin Clarke's weekend party swore they saw the pistol lifted from the wall, levelled and shot. Yet no hand held it. It couldn't have happened. but there was a dead body on the floor to prove that it had. For the victim, it was far too late for a doctor. To unmask the clever murderer, however, a house visit by Dr Gideon Fell is just what the doctor ordered. But the killer still somehow avoids taking his medicine - until Fell vows to prescribe his own remedy for bringing the mu