On August 20th, Koyomi Araragi left his home to deliver to Mayoi Hachikuji something she had forgotten, but was unable to find her. He realized he had not done any of the homework he was supposed to do, yet tomorrow was already the term opening ceremony.

Koyomi and Shinobu unexpectedly time warped back to May 13th 11 years ago. Koyomi thinks of saving Mayoi Hachikuji, who was “destined to become a ghost after getting into a traffic accident on her way to see her mother the next day – Mother's Day."

After succeeding in changing the destiny of Hachikuji, Koyomi Araragi and Shinobu Oshino returned to August 21st 11 years in the future. There, the two of them find out that their original world had been completely annihilated.

Shinobu Oshino realizes that humanity had turned into zombies thanks to the powers of Kiss-shot. Koyomi Araragi shoots up fireworks as an SOS signal, but instead they are surrounded by zombies. However, an unexpected individual arrives at the scene...