Seven friends. One weekend away. A murder no one saw coming. When a woman is found dead inside the luxurious and storm-bound Hotel Celestia, the reunion trip of a tight-knit friend group takes a dark, chilling turn. With the hotel on lockdown and the police delayed by the raging storm, off-duty detective Jeon Jungkook steps forward to help contain the situation-reluctantly drawn back into the world he tried to escape for just one weekend. But as the hours pass, questions multiply. Who was the victim really? Why Room 717? And what exactly was she trying to hide? In a place where no one can leave and time is running out, the truth is waiting behind locked doors-and not everyone has the key.