Seo Na-young, a shy and ordinary college sophomore, joins the board game club “Playmate” with pure intentions. Friendly upperclassmen, a warm atmosphere—at first, everything seemed perfect. But one day, the club reveals a completely different side. “Whoever loses the game must carry out a penalty.” At first, it was just a lighthearted joke. But as the games continued, the penalties gradually crossed the line, and Na-young finds herself confronting desires she didn’t even know she had. Even as she wants to run away, she finds herself eagerly awaiting the next game. And she realizes: once you become a player, there’s no stepping off this game board.