Jae-hoon, a ruthless CEO, needs a wife by Christmas to secure his inheritance. Min-seo, a struggling artist drowning in debt, needs a miracle. Their solution? A fake marriage contract, airtight and emotionally sterile. But when Jae-hoon insists on decorating a Christmas tree to "look married," he catches Min-seo smiling for real. And in that one moment, their perfectly planned lie begins to unravel.

But their fake life is more dangerous than they ever imagined. A conniving cousin, a secret family history, and a grandfather with a hidden agenda all conspire to tear them apart. As the holiday clock ticks down, Jae-hoon and Min-seo must navigate a world of high-stakes deception, where a single misstep could cost them everything. The only way to survive is to become a team, to trust the person they promised never to love, and to discover that sometimes, the most dangerous lie is the one you tell yourself.