Nemuri no Fuchi

Shuuhei Sazaka is a young boy who loves playing hide-and-seek. One day, he decides to play the game with his longtime friend Kaori, letting her be the one to hide. However, the fun stops abruptly when Kaori cannot be found and is thereafter never seen again. Throughout the next eight years, Shuuhei resents himself for never being able to find her. As time passes, strange "mazes" start appearing, seemingly at random. Blamed for the increasing cases of disappearances over the past years, these mysterious structures draw the attention of many, including Shuuhei himself. When he ventures into one of these mazes, he encounters something that challenges everything he thought he knew about what happened to Kaori. Nemuri no Fuchi follows Shuuhei as he tries to unravel the mystery behind the connection between the mazes and those who disappear, leading him into a world far more complex and dangerous than he could have imagined.