The Red Dragon Emperor, Issei Hyoudou, and the Occult Research Club resume their duties as summer vacation begins for Kuoh Academy students. Following their clash with Issei"s arch‑enemy Vali and the Chaos Brigade, it becomes obvious how unseasoned Rias Gremory"s squad truly is. Consequently, she and Azazel steer the club through a rigorous training schedule beneath the Underworld to ready them for looming trials.
As the group gradually coalesces, Issei will once more encounter personal moments with the club"s female members. Meanwhile, their foes strengthen and multiply while gathering allies. With Loki, the malevolent Norse deity, abruptly arriving, the arena is primed for monumental battles and formidable demons in High School DxD BorN! They also refine teamwork tactics and learn to anticipate each other"s moves. In the evenings, Issei shares stories with the girls, strengthening their bonds and confidence.
