Tsuna, Gokudera, Reborn and Bianchi are having trouble locating a staircase that would lead them to Mukuro Rokudo. Reborn concludes that Mukuro destroyed most of them to make it easier to defend their base but thinks that Mukuro is confident of winning since he cut off other escape routes. The group then continues their search and finds an emergency ladder. As the group approaches it, Gokudera notices that Chikusa Kakimoto is there and throws his dynamites, which turn out to be smoke bombs. Gokudera tells the others to go and leave Chikusa to him. Bianchi tries to persuade him to stop, saying that the virus Shamal used to cure him may cause side effects that would inflict him with pain, but Gokudera won't hear a word of it. Tsuna tries to protest too but Gokudera tells him to go and defeat Mukuro so that they will be able to have fun together again. Tsuna agrees and leaves with Reborn and Bianchi while Gokudera readies himself to battle Chikusa.
Tsuna and the others head to the third floor after exploring the second floor and Tsuna finds himself face to face with the student he met in the woods earlier. Tsuna goes to approach him, telling the others that he's a Kokuyo student hostage he met in the woods, but the kid introduces himself as Mukuro, surprising Tsuna. Just then, the group hears a sound and Tsuna looks around and sees Futa.
Meanwhile, Gokudera is dodging all of Chikusa's needles. Chikusa goes after him but notices a dynamite stuck on the wall and manages to avoid it. Gokudera then uses his Double Bombs but Chikusa is able to destroy the dynamites. However, Gokudera points out the dynamites at Chikusa's feet, which explode. Chikusa is able to recover from the attack and Gokudera tries to attack again but fails when the side effects kick in. Gokudera collapses on the wall when Ken Joshima breaks through it and attacks him.
Meanwhile, Tsuna and the others approach Futa. Tsuna is relieved to see him and tells him to stand back since it's dangerous. However, Futa pulls out a knife and stabs Bianchi, while Mukuro watches them with an amused expression on his face.
Elsewhere, Gokudera is bleeding due to Ken's attack and collapses down a flight of stairs. As Gokudera lies immobile on the ground, one of Birds' birds arrives and begins to sing the Namimori Middle School anthem. Hearing this, Gokudera throws a dynamite on the wall while Chikusa and Ken approach him, preparing to finish him off. The explosion creates a hole in the wall and Hibari walks up, readying himself to fight the two.
Note: Bold + Italicized = First Appearance