Issei wakes up to find that the battle is over, and he has lost. Rias and the others are at a party in honor of her engagement to Riser, but with some help from Grayfia and Asia, Issei decides to crash it, rescue Rias, and bring her home with him!

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.