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.

Aoi and the Red Tails return to Ishiyama High to deal with Oga, despite not knowing who he is. When Takayuki drags Oga to meet her, Aoi is shocked to find Oga is the one she met at the park, although he doesn't recognize her back. Aoi starts to fight him using powerful bokuto attacks that cut through glass, but he manages to dodge all of her attacks. Impressed by her strength, Oga asks Aoi to become Beelzebub's mother which causes her to become embarrassed and run off. Afterward, Aoi seems to develop feelings towards Oga. Meanwhile, another delinquent gang plots to take down Aoi.

As Kanzaki tries to come up with a new special move to beat Oga, his followers suggest the key to Oga's power is having Beelzebub on his back. Thus, Kanzaki starts training with a weighted baby doll on his back. When that plan doesn't work, they try finding a living substitute, which end in more embarrassing results. Meanwhile, Oga takes Beelzebub to the park where they once again meet Aoi, who has lost track of Kouta. Kanzaki coincidentally finds him and deems him a worthy substitute for Beelzebub. Whilst playing with him, he figures out the key to performing his new special move. After returning Kouta to Aoi, Kanzaki performs his special move, though it just leaves everyone confused. As Kanzaki leaves, Oga admits his move was surprising.

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.

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.

After being shocked early in the morning by Baby Beel, Oga's enthusiasm to find someone new to pass Beel onto is temporarily reborn, and upon hearing rumors of six students who excel both academically and athletically, he goes off searching for these six in the hopes that they will impress Baby Beel. Oga, accompanied by Aoi, goes searching for Kazuya to get more information about the 6 Holy Knights. Meanwhile, Furuichi runs into an old friend, Miki. He warns Furuichi to stop Oga getting involved with the six, and tells him that the six wear badges to identify them as Holy Knights, before promptly revealing himself to be one of them. Oga finds Azusa while looking for Kazuya, and is quickly interrupted when two of the Knights show up, revealing themselves to be Alex and Sakaki. Sakaki tests Aoi's strength first by attacking her with a wooden sword, while she only has a ruler she borrowed from Azusa to defend herself with. Aoi cuts the tip of Sakaki's sword off during his attack, proving herself to be the more skilled swordsman. Oga refuses to fight his opponent, Alex, and instead quizzes him while attempting to dodge his attacks. Alex gives up when he realizes Oga is not taking the fight seriously, and the two knights leave the scene.

The festival is underway, and Azusa is trying to run a Maid café. Furuicihi offers to help, and Azusa and her friends obey his commands blindly due to his reputation as 'The Strategist'. Furuichi persuades many of the Red Tails to dress up in Maid uniforms, claiming that this is a preliminary battle against a café that the 6 Holy Knights are running elsewhere. Hilda also gets involved, and remodels the café to be more formal. Some rowdy guests from Teimo High enter the cafe acting unruly, whom Hilda is quick to discipline.

Hilda recovers and apologizes for everything and being unable to help. Oga decides to become stronger in order to protect everyone and so seeks for Aoi's grandfather to train him. Oga's younger sister is revealed to be a member of the Red Tails. After seeing Kouta come out of the shrine Oga realises that Aoi Kuni is actually Aoi's cousin. Oga and Teima Shadow receives pointless training from Aoi's grandfather. Saotome and Tojo talk about the incident, however Tojo doesn't understand everything about demons and mistakes them for bears and Saotome's friends.

The episode opens with a distinct sci-fi feel, before moving into the game, where the Ishiyama group are in the middle of getting their asses handed to them. They are unable to do anything against the tank. Then Yuka shows up, driving a giant robot called the Crazy Frog. She crushes the tank, and proceeds to kick and tap dance all over the other vehicles. Up until she steps on a mine and loses the tank. Tatsumi's training goes more like an aerobic workout, complete with lame musical accompaniment. He complains about this, calling out for being an exercise, and not training. Meanwhile the gamers run into more trouble when En's team start using an invisibility cheat. Himekawa realizes what they are doing, and goes to prepare some countermeasures. While Tatsumi does pushups, Saotome tells him that Tojo asked to be trained, and if he isn't careful Tatsumi will be overtaken. Saotome uses a recording of Tatsumi's voice to make a training partner who has all his hidden strength.

Oga is trying to think of a way to perfect Super Milk Time before they're attacked again whilst Nene and the rest of the Red Tails are trying to get Aoi back into the group by holding a fake meeting at Aoi's place and so persuading her. Aoi's demon magic is revealed to be thanks to Koma, a perverted demon whom she acquired at Mapputatsu Temple. Oga has found a new milk bottle which will hopefully help Super Milk Time and is asking Furuichi to try it, who is obviously reluctant as he is "busy". Meanwhile, St Marian's High School for Girls have declared a battle against the Red Tails in order to overtake the Southern Kanto region as well as the North, however they are unknowingly defeated by Koma who runs around touching each of them and so making them feel weak and uncomfortable therefore being unable to fight.

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.