Dr. Molyneux, the elderly botanist who loves nothing more than his mimosa plants, also secretly authors crime novels under the pen name Felix Chapel -- but only because his wife insists they need the money. As it turns out, Molyneux gets the stories from his adopted daughter Eva, who in turn gets them from the milkman, who's madly in love with her. Everything would be fine if it wasn't for Chapel's relative, the Bishop of Bedford, who is crusading against Chapel's ""dangerous"" novels. The Bishop is not quite wrong because a man known as the Butcher Killer blames Chapel for his own crimes. When the bishop invites himself for dinner at Molyneux's house, hilarity ensues.