Modern man Leo Forrest dies, travels back in time, becoming a foolish ancient Live-in Husband. He exposes his wife Clarice Blair and her brother's plot, divorces her, and marries Grand Princess Seraphina Sterling. He outsmarts corrupt officials, cracks a bank scam, develops a miracle drug, and kills Julian Blair. Facing The Beirong invasion, Leo Forrest shoots the enemy chief, rallies troops, and stands with the Princess to defend the country.