Jill is executed by her fiancé, the crown prince. Before she dies she is thrown back in time six years to the party where the engagement began. Determined to avoid her fate, she immediately proposes to the man standing behind her—who turns out to be Emperor Hadis, the terrifying Dragon Emperor she knew only as a future enemy. Completely charmed by the food he gives her, she makes a life-altering decision: she will reform him, and make him happy.

Jill is a tomboyish, physically capable young woman whose mental age is sixteen despite her ten-year-old body at the series' start—a conceit the story handles through action-comedy rather than romance in the early volumes. She is relentlessly determined, loyal to a fault, and motivated by the simple conviction that Hadis deserves to be happy. Hadis is a delightedly unpredictable emperor whose warmth beneath his terrifying exterior is Jill's greatest project.

Across seven volumes, Jill and Hadis navigate treacherous imperial politics, family betrayal, military rebellion, and rival nations—Jill always throwing herself into danger to protect and reform the man she chose. Their relationship deepens from absurdist comedy to genuine partnership, with Jill's stubborn loyalty and fighting ability repeatedly saving them both from the disasters her foreknowledge couldn't predict.