Behemoth visits St. Ishiyama to find Oga and Beelzebub, but he gets welcomed by Zenjuro, Ittousai, and the principal. Hilda holds Oga down while they watch the fight. Meanwhile, Furuichi and the delinquents arrive at Akumano Academy. They stumble upon the Pillar Generals. Agiel attacks only to meet Aoi who arrived in the nick of time. Will Aoi defeat Agiel?
Hilda notes that Oga and his friends are acting funny and that they're scheming something bad. Oga and Beel deny this, but do so in such a poor manner that Hilda easily notices they're lying. After Oga introduces the next episode, Hilda begins to think of a new dance for Baby Beel in place of the Pudding Pudding dance. Oga responds with a fake laugh.
Himekawa introduces himself and tells everyone how he makes his "super cool" pompadour: by hardening it with a hair gel called Pomade. Furuichi ignores him and mentions a man showing up. Himekawa thinks he's referring to the Legendary Warrior, Super Pompadour. Oga asks who that is. After Himekawa introduces the two-part episode, Oga becomes surprised that the Great Demon Lord is showing up, while Himekawa ignores him and worries about his lost pompadour.
When Black Beel has gone missing, Zenjuro urges Oga, Furuichi, and Beel to look for him before something bad happens. Meanwhile, Himekawa who has kidnapped Black Beel for his close resemblance to a lucky statue experiences great luck and wealth. Somehow, Black Beel has grown gigantic.
Oga ,Furuichi and their teacher (which was the Spellmaster) was searching for the black version of Baby Beel. Oga thought that it was so bored that it ran away. But actually it was because of Himekawa.They asked some girls if they saw someone with a baby, and they answered that they saw a nice looking, hot guy that smelled so nice. He took it because he believes that it was the key for their family to be more successful. In the end, Black Baby Beel was reunited with Oga's teacher.
The show opens seeing the 2 pillars who got beaten in jail, and 2 other pillars talking to them. One is Lamia's mom. They then cut to the main gang who are tired from playing video games. Shiro acts as Lamia while talking to En. He speaks like a ditzy schoolgirl, but En buys it.
Oga begins his training with Ittousai while Furuichi and Lamia enlists the help of their Ishiyama classmates to search for Lord En. Can Oga and Beel complete their training in time and will Furuichi and Lamia find Lord En before he destroys the city with his army?
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.
The match between Ishiyama and the 6 Holy Knights is here, and this is not your usual volleyball! With their pride and their educational future on the line, the Ishiyama gang puts it all out there on the court! Will Furuichi the Strategist be their trump card?
Finding Alaindelon's daughter rather attractive, Furuichi vows to rescue her while Gare and Edda leaded him to Oga and Lamia in the village of thieves where Alaindelon's daughter, Angelica is trapped. The rescue runs smoothly until a large Demon named Vlad's Master is awakened and terrorizes the village in which Beelzebub suddenly growed bigger and larger to fight it off.
Baby Beel's fear of insects prompts Oga to give him some special training up in the mountainous village of Mapputatsu. There, he stumbles across Kunieda carrying Kōta in the disguise she wore at the park with her grandfather. While Oga is still unaware of her true identity as Kunieda, her grandfather develops an interest in him.
The Demon King sends Beelzebub some summer homework, containing a notebook which brings anything drawn in it to life. Next, Hilda brings Oga to Ishiyama High to collect prints of rare, powerful beasts, aka the delinquents, by whacking them with a giant fly swatter. During the chase, Beelzebub ends up planting several carnivorous Demon Plants, one of which grows into a massive giant causing havoc until Oga destroys it.
Beelzebub is currently in a phase of non-stop urination that threatens to flood the city. Hildegarde manages to temporarily stop it with an interdimensional diaper, but in order to stop it completely, Oga decides he needs to get a super absorbent daiper advertised on telly. Upon reaching the supermarket only to find the brand had already sold out, it is taking hostage by a group of thugs. As Oga probes everyone to see how ruthless they are, Beelzebub's diaper gets stuck on the leader's gun. Whilst the leader considers raising Beelzebub, Oga ends up changing his mind and beats him, before they decide to hover Beelzebub over the ocean to finish urinating.
When Oga loses some food for Beelzebub and he starts to get hungry, Oga instead uses up a vending machine's worth of yoghurt drink, revealed to be the favourite of the second year delinquent, Hajime Kanzaki. Figuring he may be worthy of dumping Beelzebub on, Oga goes to see him under the pretense of becoming his henchman. After beating his current henchman, Oga is asked by Hajime to throw him out of the window, but instead decides he isn't worthy based on Beelzebub's expression and knocks him out instead.
Hildegarde presents herself to Oga's family in the wrong way, giving them a different view of the situation. She also informs Oga that if he is more than 15 meters away from Beelzebub, his cries may destroy the city. Whilst dealing with this situation, Oga comes up with the idea that, if he can find someone more strong and ruthless than him, he can dump Beelzebub on him and be free.