Tsuna, Gokudera and Yamamoto are talking about the summer vacation ending abruptly when Reborn, wearing his autumn camouflage Chestnut suit, arrives. While Tsuna scolds him for coming to school again, Reborn tells him that they have to make a family hideout. Yamamoto and Gokudera happily agree and Reborn tells them that their hideout would be the Reception room since the furniture, view and geographical location is good. Yamamoto and Gokudera head toward the Reception room with Tsuna reluctantly following.
As Gokudera and Yamamoto enter the room, they are surprised to see Hibari inside. Hibari notices Gokudera's cigarette and uses his tonfa to put it out, much to the group's surprise. He then comments on them being weak for forming a group and tells them that he wants to bite them to death. At that moment, an oblivious Tsuna enters the room and is immediately attacked by Hibari who sends him flying. Gokudera and Yamamoto try to retaliate but fail and end up unconscious. Tsuna then gets up and sees Yamamoto and Gokudera unconscious. As Tsuna tries to make heads or tails of the situation, Reborn shoots him with the Dying Will Bullet, giving him the strength to fight back. Hibari is able to dodge Tsuna's attacks and smashes him on the chin with his tonfa. Thinking that he defeated Tsuna, Hibari turns to beat up the other two but sees Tsuna standing up. Tsuna puches Hibari in the face and uses Leon's slipper form to smash Hibari's head, angering Hibari. Hibari tries to attack Tsuna but is stopped by Reborn. Hibari comments on Reborn's strength and Reborn detonates a bomb, causing Hibari to leave.
After Tsuna, Gokudera and Yamamoto recover, Reborn explains to them that he intentionally wanted them to meet Hibari so that they could train in a real-life battle. Tsuna panics, thinking that Hibari will have his eyes on them, while the other two tries to calm him down. Reborn says to himself the Hibari would be a useful guy in the future. Elsewhere, Hibari is thinking about Reborn, wanting to see him again.