Issei Hyodo's first date with his new girlfriend ends poorly when she turns into a monster and stabs him in the stomach. Luckily, he's saved by Rias, the buxom president of his school's Occult Research Club. And then, things really start to get weird...

Surprise! All the members of the Occult Research Club are devils, including new-recruit Issei, who's having difficulties figuring out the whole "demonic power" thing. Maybe he'd have better luck if Fallen Angels stopped popping up and trying to kill him.

Kiba becomes entrenched in battle against Karlamine, one of Riser's knights, while Akeno fights Yubelluna, his queen. Meanwhile, Issei takes on Ravel and the other remaining pieces. Rias launches an all-or-nothing sneak attack against Riser.

Issei is back with Rias and Asia living in his house, and Kiba starts acting weird when he sees a picture of a holy sword at Issei's house.

Issei battles Vali and discovers hidden depths to his power as the Twin Sky Dragons face off.

Summer break is coming up fast for Hyodo Issei, but all his plans are put on hold when he finds out he is to accompany Rias for her visit back home to the underworld! A new adventure is about to begin and all the while Koneko is not acting herself.