When a high-stakes architectural project puts sworn rivals Lee Eun-ji and Kang Tae-joon back in each other's orbit, one impulsive photo under the mistletoe ignites a scandal neither can escape. Forced into a fake engagement to win the deal of their careers, every public smile hides a private war-and every staged touch blurs the line between hate and something far more dangerous. This Christmas, love and rivalry will collide under Seoul's glittering lights, and only one can win.