The infamous series of unexplainable murders in Hinamizawa have been solved and the chains of fate have broken due to the efforts of Rika Furude and her friends. Rika believes she has finally obtained the normal and peaceful life she desired with her friends; however, she is proven wrong when the wheels of fate begin turning once again after an unfortunate accident. Rika suddenly finds herself in a perfect world, the constant cycle of brutal killings having never taken place, where all of her friends are content and satisfied. Not wanting to abandon the world that she fought so hard for, she learns she must destroy an essential key to get back. But can Rika abandon the faultless world she is given the chance to live in, after all of her battles have brought her this far?

The year is 1996, and second-year high school students Haruo Yaguchi, Akira Oono, and Koharu Hidaka live their lives as passionately about video games as they were five years ago. Brought together by arcade games, what began as a healthy rivalry and friendship has turned into something more. As they endeavour towards understanding their unfamiliar feelings, they work with allies, navigate high school, and find that, although life has its many challenges, there's always a game or two they can rely on.

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.

Rika Furude and her group of friends live in the small mountain village of Hinamizawa; in June 1983, they welcome transfer student Keiichi Maebara into their ranks, making him the only boy in their group. After school, they have fun playing games and spending each day living their lives to the fullest. Despite this seemingly normal routine, Keiichi begins noticing strange behavior from his friends, who seem to be hiding the town's dark secrets from him. Elsewhere, a certain person watches these increasingly unsettling events unfold and remembers all the times that this, and other similar stories, have played out. Using that knowledge, this person decides to fix these broken worlds. However, when certain variables change, the individual is faced with a horrifying realization: they have no idea what to expect or how to stop the impending tragedy.