After a bitter quarrel with his wife, Jan (Patricia Plunkett), Stephen (Derek Farr) goes off on a bender, picking up bar hostess Grena (Joan Dowling) along the way. As the evening progresses, Stephen gets involved in a fracas in his own home. When it's all over, Grena is lying on the floor, apparently dead. Upstairs neighbor Michael (Dennis Price), sensing that something's amiss, decides to indulge in a little blackmail. The ensuing complications include a most ambulatory "corpse" and a misapplied glassful of poison.