Takayuki is dragged away from his tropical summer vacation against his will to join Oga and Beelzebub to a public pool, though Oga is soon shocked by the fact he could've gone to the tropical resort himself. Whilst chatting with the Red Tails, Takayuki is approached by some delinquents from his old middle school and ends up going against their leader, Takashima, when they start hitting on the girls. Takayuki tries to hide in the pool, but Takashima calls more of his men and tricks the lifeguard into evacuating the pool, leaving Takayuki and a stunned Oga. As Takayuki becomes surrounded, he forces Beelzebub to cry in order to shock all the delinquents before facing Oga's wrath.

Furuichi and Oga survey the school from the roof searching for emblems on people's shirts, and Azusa ends up tagging along in their search. Two students from St. Ishiyama are seen hassling two of Aoi's gang, causing Shiroyama to interject, telling them to leave. The two disgruntled students are offered a free punch by Shiroyama as compensation for breaking off their advance on the girls. They roll a large weight onto Shiroyama, hospitalizing him. Kanzaki bursts into the classroom the two boys are in later that day to get vengeance, only to be knocked out by Miki in one blow. Miki the invites the students of Ishiyama High to meet him on the roof after school. Himekawa, Natsume, Furuichi, Oga and Aoi all go to the roof after school, though Furuichi stays in hiding.

Lamia asks Fruichi to find Baby Beel's brother but when they went to the game center, they find Kanzaki,Himekawa, and Yuko. Furuichi asks them for help. Meanwhile Aoi and Oga went for training to be strong.