The anime takes place on the screw-shaped island country of Nejigajima and follows the two "Bokyabots" Hebot and the Yurui Prince Nejiru as they collect different "Bokya Neji" screws. When the Bokyabots wear the Bokya Neji screws on their heads, they're able to compete in "Bokya Battles," battles for who can think up and tell the best jokes. (Source: ANN)

High school student Issei Hyoudou is your run-of-the-mill pervert who does nothing productive with his life, peeping on women and dreaming of having his own harem one day. Things seem to be looking up for Issei when a beautiful girl asks him out on a date, although she turns out to be a fallen angel who brutally kills him! However, he gets a second chance at life when beautiful senior student Rias Gremory, who is a top-class devil, revives him as her servant, recruiting Issei into the ranks of the school's Occult Research club. Slowly adjusting to his new life, Issei must train and fight in order to survive in the violent world of angels and devils. Each new adventure leads to many hilarious (and risqué) moments with his new comrades, all the while keeping his new life a secret from his friends and family in High School DxD! [Written by MAL Rewrite]

The Red Dragon Emperor, Issei Hyoudou, and the Occult Research Club are back in action as summer break comes for the students of Kuoh Academy. After their fight with Issei’s sworn enemy, Vali and the Chaos Brigade, it is clear just how inexperienced Rias Gremory's team is. As a result, she and Azazel lead the club on an intense training regime in the Underworld to prepare them for the challenges that lie ahead. While they slowly mature as a team, Issei will once again find himself in intimate situations with the girls of the Occult Research Club. Meanwhile, their adversaries grow stronger and more numerous as they rally their forces. And with the sudden appearance of Loki, the Evil God of Norse Mythology, the stage is set for epic fights and wickedly powerful devils in High School DxD BorN! [Written by MAL Rewrite]

After rescuing his master, Rias Gremory, from the Dimensional Gap, Red Dragon Emperor and aspiring Harem King Issei Hyoudou can finally return to his high school activities alongside fellow members of the Occult Research Club: Yuuto Kiba, Asia Argento, Xenovia Quarta, and Irina Shidou. The group soon embarks on a school trip to Kyoto. While peacefully visiting a temple thanks to Rias' spell, an attacking group of local youkai breaks the calm atmosphere. Once the altercation ends, the club learns that the mythical nine-tailed fox that protected the city was abducted and that someone has framed them for the act. Issei and his friends will now have to fight to protect the city and save their school trip from a planned disaster! In the meantime, Rias, who had to stay in Tokyo with Akeno Himejima and Koneko Toujou, grows increasingly restless to have left the perverted Issei alone with the other girls of the Occult Research Club. Beyond this vague anxiety, what is the exact nature of the feelings Rias has been struggling with for the past few months? [Written by MAL Rewrite]