This is a drama between Kang Yeo Joo (Jo Yeo Jung), a criminal novelist who only thinks about how to kill people, and her husband, Ha Woo Sung (Go Joon) who is a divorce lawyer who wrote a memorandum saying, ‘If you cheat, you die’.

For her work, best-selling crime author Yeo Joo researches how to make a murder look like an accidental death. Next to her is her younger husband, Woo Sung, who is a family man and works as a divorce lawyer. Woo Sung still thinks he's a sexy, attractive partner, and lives on with his wonderful marriage life. However, lately, Yeo Joo, who would rather be a widow than a divorcee, starts finding some of his behavior suspicious. Could he be cheating on her? Could Woo Sung possibly be enjoying a thrilling affair behind her back? Yeo Joo tells it straight: If he cheats, he will die.