On campus, Issei Hyoudou (voiced by Yuki Oo) is known as a "pervert". Thanks to this, Issei still lives a lonely life without a girlfriend. This is destined to be an unusual day. First, Issei actually received a confession from a beautiful girl; then, when Issei was about to start his dream of a happy date, he was decisively killed! When Issei opened his eyes again, the red-haired woman in front of him told Issei that she resurrected him who had died, and from today on, he would become her slave. The red-haired woman is called Rias (voiced by Yoko Hikasa), and her true identity is a demon. The woman who attacked Issei belongs to the ranks of "fallen angels". From the difficult terms such as "war" and "artifact" in Rias's mouth, as well as the continuous attacks from the fallen angels, Issei knew that his simple and happy campus life was about to come to an end.