Summer's here, and before anyone knows it, the rating game between the Gremory and Sitri houses is scheduled to take place in the devil realm Issei and the gang jump right into some hellish training, but something's not right with Koneko-chan...?

Summer's here, and before anyone knows it, the rating game between the Gremory and Sitri houses is scheduled to take place in the devil realm Issei and the gang jump right into some hellish training, but something's not right with Koneko-chan...?