In the rural town of Yushibana, the Ashiya family holds much of the wealth. After they discover a rare gemstone, a showing is scheduled in Ashiya Tower, drawing the attention of many of the townspeople. However, during the exhibit, the tower is flooded with smoke, activating emergency shutters that trap eight people inside. With no way out, they must find the truth behind their imprisonment and grapple with an increasingly complex series of unnatural events.