A decade ago, mankind witnessed the deadly potential of weapons caused by the Great War. To avoid another catastrophe, governments worldwide have resorted to espionage to fulfill their agendas. In the Din Republic, Lily is an enthusiastic young girl who aspires to become a spy and serve her nation. However, she begins to doubt her abilities, as she struggles to perform well academically. Lily's passion is reignited when she is offered provisional graduation by joining the spy team Lamplight, which she eagerly accepts despite the enigmatic nature of the opportunity. Upon arriving at her destination, Lily is surprised to find six other girls waiting there, all of whom have faced their own academic difficulties as well. A mysterious man named Klaus soon appears and reveals they must complete an "Impossible Mission": to infiltrate the Galgad Empire after just one month of training. Although skeptical, the girls eventually agree to work together under Klaus' guidance—as this might be their only chance to prove their worth as spies.

The misadventures of Issei Hyoudou, high school pervert and aspiring Harem King, continue on in High School DxD New. As the members of the Occult Research Club carry out their regular activities, it becomes increasingly obvious that there is something wrong with their Knight, the usually composed and alert Yuuto Kiba. Soon, Issei learns of Kiba's dark, bloody past and its connection to the mysterious Holy Swords. Once the subject of a cruel experiment, Kiba now seeks revenge on all those who wronged him. With the return of an old enemy, as well as the appearance of two new, Holy Sword-wielding beauties, it isn't long before Issei and his Devil comrades are plunged into a twisted plot once more. [Written by MAL Rewrite]

Ichirou Kuga has suddenly found himself taking on the responsibility of caring for his two younger siblings after their father's untimely death. To make ends meet, Ichirou rents out rooms in the apartment complex he inherited and works full-time as a shoujo manga artist. However, his manga sales are low, his assistants have recently left, and deadlines are fast approaching. As stress threatens to overtake Ichirou, salvation comes in the form of an extremely competent novice artist, Shiori Goshiki, who becomes his new assistant. With her skills, they are able to tide over the difficult situation, and things begin looking up. But in a bizarre accident, a supernatural experience unfolds between Ichirou and Shirou, which leads her to declare them engaged. With this seemingly innocuous action upending his life, Ichirou now has to manage his new and peculiar relationship with the mysterious girl, all the while following his own passion and fulfilling the duties that rest on his shoulders.

Third season of .