Baby Beel comes down with a fever, and Oga's link to him and his never-ending shocking comes to an end. Hilda and Baby Beel disappear, and when Oga goes looking for them he finds Baby Beel stuck on Tojo's back! The battle with the top of the Ishiyama TKKH is here!

The Great Demon Lord decides to send Baby Beel some summer homework on a whim. The gang helps Baby Beel do the homework as best they can, but if they mess up how to use the items in the kit, all of humanity is doomed! Will they actually be able to turn it in on time and in one piece?

Furuichi is called back from a resort on a tropical island where he was vacationing with his family to go to the public pool with Oga. At the pool, Furuichi runs into a nasty upperclassmen he knew from middle school, and it's not just him, but Nene and the other Red Tails that are in trouble! Will Furuichi, "the strategist" finally make his move?!

Oga hears about the legendary Tojo, the final and strongest member of Ishiyama's TKKH, from Furuichi. And right away, he goes for a showdown! Well, if he knew where Tojo was. Thanks to Himekawa's digging, Oga, Hilda, and the rest head to the beach where Tojo is supposed to be working part-time...

Kanzaki is thinking hard about why he's unable to be a match for Oga, and tries to perfect a new special move, when Shiroyama realizes the crucial difference... Oga has a baby on his back! Shiroyama and Natsume help Kanzaki go through intense "BoB" training!

It's the Ability Assessment tests for Ishiyama High, the den of delinquents. Oga tries studying for the test, for once. Baby Beel and Hilda have gotten used to various customs in the Human World and report on Baby Beel's growth to the Great Demon Lord.

Oga's family is seriously worried about Baby Beel's night crying, as it's causing everyone in the entire town to lose sleep. They try all kinds of things but nothing works. Oga heads to school, completely exhausted, as do the other students looking for a fight. Everyone ends up asleep, dreaming...

Himekawa lives by the motto, "there's nothing that money can't control." In order to get revenge on Oga, he uses the power of money to work behind the scenes in plan after plan to defeat him, but Oga keeps getting the upper hand somehow...

A cat follows Oga home one day. Baby Beel challenges the cat for Oga's attention. Once the showdown is over, they are surrounded by stray cats, and Baby Beel stands tall to defend! This is the start of a friendship between 1 baby and 1 kitty.

Hilda hears about Kunieda Aoi from Oga and wants to find out more. She goes in search of her to test her skills. At the same time, there's someone with a half-baked scheme against Oga using Aoi's protective attitude.

The Crimson Queen of the TKKH, who holds the deep confidence of all the women, has returned from subjugating all the Ladies of North Kanto! Hearing the rumors, Furuichi drags Oga along in trying to get a glimpse of her. Before long the Queen appears! She tries to bring the iron hammer down on Oga, who in her absence has defeated two members of Ichiyama's TKKH, and even destroyed half the school, but when she sees Oga appear in front of her...!?

The Park Debut... It is when you first join the community of mothers who bring their young children to the park. That day, Oga took Baby Beel to the park for his nerve-wracking debut... But the rumored BoB Brawler only manages to freak out the local mothers. During this debaucle, Oga meets fellow high schooler Kunieda Aoi and her much younger brother Kota, where he suddenly asks her to "do it" with him?!

A - Hilda brought back a bunch of toys from the Demon World for Baby Beel. When Oga and Hilda were assemble one, a horrible accident occurs! B - The Zebul Spell expands when one does evil. So won't it contract if you act like an angel? ...thinks Oga, who uses a Play Doctor toy with Beel as the doctor to try and heal patients. It's time to play Demon World Doctor!

On the back of Oga's fist a mark appears that is proof of his contract with the son of the Demon Lord, Beelzebub... The Zebul Spell. After hearing that the demonic power grows as well as the Zebul Spell the more he gets into fights and runs wild, Oga decides not to fight anymore to avoid that situation. However, Himekawa Tatsuya, heir to the Himekawa Zaibatsu and one of Ishiyama's TKKH like Kanzaki, is secretly plotting to do Oga in himself, and gives the command to his lackeys...

When Oga wakes up one morning, he's floating in a great pool of water... However it is actually Baby Beel's pee, as it is "urination season" right now in the Demon World. Oga is concerned about the entire city being inundated and humanity's imminent destruction, so he takes Baby Beel to the drug store to buy some disposable diapers. While he's there, a bunch of bank robbers a take Oga, Baby Beel, Hilda and Furuichi (who were chasing after him) as hostages.

Oga loses the powdered milk that Hilda prepared for him, and instead buys a bunch of "Yogurty" from a vending machine for Beel. But it turns out that's the favorite drink of one of Ishiyama's Big Four, the "Ishiyama Tohoshinki"; the third year Kanzaki Hajime. Oga hears about how horrible and ruthless a guy Kanzaki is, and runs into the third year classroom to try and dump Baby Beel off on him. When he sees Kanzaki's evil looking face, Oga thinks that this just might be his chance!