“Let’s have a little reunion, just the four of us.” Lemon, Cyan, Murasaki, and Kurone—a group of four close friends who were considered “oddballs” back in middle school. Over time, they drifted apart, each leading their own high school lives. In the summer of their third year in high school, Korone—the lively mood maker who brought the oddballs together—reaches out after a long time. Looking forward to their reunion, they all arrive at the meeting place… or so they thought. When they regain consciousness, they find themselves in a small room with no exit. The room is decorated as if themed after Alice in Wonderland. In each corner of the square room, there is a chair and a table for each girl, as well as a lovely tea set. And also, long chains that extend from each chair, connected to the collars around the girls’ necks… The “reunion” has become a death game—a battle of life and death to settle the past…!