After clearing Bad-Mouth Sugoroku, Yuichi and Tenji find themselves trapped in a dark cave for three days. During their isolation, Tenji makes the shocking revelation that he had already experienced a Tomodachi Game in the past. Meanwhile, a team of new opponents lies in wait outside, anxious to challenge the two partners to a grueling third game.

With "true genius" Kei controlling things from the shadows, Group K succeeds in finding Tenji. Facing the "worst thing that could have happened," Tenji makes a phone call to a certain individual. The third game, Friendly Hide-and-Seek, then reaches its conclusion. While the two groups struggled to outwit each other, Shiho, Shibe, and Yutori, who had been temporarily released for the third game, returned to school only to be met with cold stares from their classmates.