Struggling artist Han Ji-eun thinks she's signing a lease renewal. Instead, she accidentally signs a contract meant for a billionaire's fianc e. Her life is now bound to the coldest CEO in Seoul, Kang Min-jun-a ruthless man who sees people as pawns and love as a liability.
With her family's future at stake and a hidden one-billion-won penalty hanging over her head, Ji-eun is forced into a twisted fake engagement. The Christmas season becomes a high-stakes performance, a dangerous dance where every public kiss is a lie and every stolen glance hides a secret. But as they navigate a world of corporate backstabbing and family secrets, Ji-eun discovers the man behind the ruthless mask is just as trapped as she is.
As the line between deception and reality blurs, they face a final twist that could either set them free or shatter them completely. In a Christmas world of glittering lights and cutthroat deals, can a fake love become a real one, or will their one signature bind them to a dark and dangerous end?