An Act of Villainy

On the way home from the theater, Amory Ames and her husband Milo are walking through London's West End when they run into wealthy investor and former actor Gerard Holloway. Holloway is an old friend of Milo's, and he invites them to the dress rehearsal of his new play, in which he has cast his mistress, actress Flora Bell, in the starring role

He quickly admits to Amory and Milo that he has an ulterior motive―Flora has been receiving threatening letters to her dressing room, and he needs their help in finding the mysterious sender. Despite Amory's conflicting feelings―after all, not only is she friends with Holloway's wife, but what does the disintegration of the Holloways' marriage mean for her own rather more delicate relationship?―Amory's curiosity gets the better of her, and she starts making inquiries.

It quickly becomes clear that each of the members of the cast of the play have reason to resent Flora, and when someone is killed on stage after the opening night, Amory and Milo are once again thrust into the murderous limelight.