The Impostor's Diadem

Matthew, who runs Bluewave Holdings, hands the company over to his deputy Zoe before a business trip. He means to propose to her when he gets back. While he is away an intern, Melody, announces she is carrying his child. She starts calling herself the boss's wife, orders the staff about, humiliates them, and wrecks a deal worth three billion. Zoe keeps quiet and gathers evidence of everything Melody does. Matthew comes back and lays the evidence out. Melody was never pregnant by him. The claim was arranged with his adopted younger brother, who cannot father children and whose woman Melody is. Melody goes for a knife once this is out, and the police are brought in.