Episode 0 of Towa no Yuugure.

Kaede Yakumo, an ordinary 17-year-old high school girl, unexpectedly wakes up in another world with only her backpack alongside her. After aimlessly wandering around trying to understand her whereabouts, Kaede gives up and decides to look for anything useful in her belongings, which leads her to discover an unfamiliar book. Inside, the book lists recipes for producing potions using a simple command word, create, and a note telling her to think of this new experience as a game. With a clear path laid out in front of her, Kaede vows to use the potions she crafts for her survival—and hopefully find the person who unfairly transported her to this world in order to return home.

Gen Kinokura is a solitary camper looking for time away from the crowded city to refresh his mind and enjoy nature. But one day, Gen meets Shizuku Kusano at the supposedly empty campsite. A complete beginner at camping, Shizuku tries to settle in with Gen despite his protests. Gen reluctantly gives in once he notices her lackluster preparation. Offering advice for her next trip, Gen believes their interaction ends on this occasion. However, Shizuku decides to join his future solo outings to learn more about camping. Although no longer on their own, the two set rules on how to camp together, allowing them a give-and-take experience while still relishing the atmosphere in a form of solitude.

After Jinta and Suzune ran away from their home as children, they were taken in by Motoharu—the virtuous sentinel of Kadono Village—and his daughter, Shirayuki. The settlement was ruled by its shrine maiden, Itsukihime, whom only a select few were allowed to interact with. When Itsukihime passed away, Shirayuki was appointed in her place. Wishing to stay in contact with her, Jinta worked diligently for years and was finally selected as the next sentinel. As the protector of the village, Jinta's duty is to eliminate any threats. One day, he encounters a demon in a nearby forest. At the end of the battle, the demon makes a proclamation about the destined ruler of all demonkind. He attaches his severed arm to Jinta, turning him into an unaging demon man. By the time Jinta comes to, Kadono is on fire. Suzune has transformed into the demon from the divination, and due to a series of misunderstandings, she murders Shirayuki and flees. Devastated, Jinta cannot forgive Suzune for her actions; he departs on a journey to find her. As Jinta travels around Japan across the eras, he endeavors to protect as many people as possible from aggressive demons. In his quiet moments, he contemplates what he should do when he once again faces his childhood friend.