Final Defense Block

Tsuna flies through Merone Base with a mission and that mission is to find Shoichi Irie and the white, round device in his laboratory. Irie tries to interfere with Tsuna's movements by moving Merone Base's blocks. With Spanner behind him, Tsuna cannot shake off a homing missile, but he is able to fend it off with chaff and flame shots that Spanner modified. He is later intercepted by the Phantom Knight, Genkishi.

Tandis que Kyoko et Haru espèrent le retour de l'équipe, Tsuna avance vers la salle de recherches Millefiore aidé par Spanner. C'est alors que Shoichi, très embarrassé par sa progression dans la base décide de mettre son arme ultime sur son chemin : Genkishi.

Tsuna insieme a Spanner cerca di raggiungere il laboratorio di Shoichi, che però ha preparato una serie di trappole per impedirgli di arrivare.

入江正一操纵基地里的各种防卫区域，要阻止阿纲等人朝着研究室前进，不过阿纲和史帕纳联手克服所有难关，使得入江正一逼不得已动用最终防卫区域。就这样，最强的剑士幻骑士出现在阿纲面前……