Nihon e Youkoso Elf-san.

Since childhood, Kazuhiro Kitase has entered a fantasy world whenever he sleeps, spending years of dreamlike adventures there and befriending an elf named Marie. He assumes it is simply an unusually vivid dream until the two encounter a dragon in ancient ruins and are consumed by its fire. Kazuhiro wakes in Japan believing the adventure has ended.

Then Marie wakes beside him in his room. For the first time, the elf experiences real-world Japan, from convenience stores and trains to hot baths and unfamiliar food, while Kazuhiro tries to understand how she crossed over with him. They soon learn that travel may work in both directions, creating a life split between magical exploration and the simple joy of showing Marie everything Japan has to offer.