Amanosora is a small town of around 60,000 people, formed ten years ago from the merger of the villages of Tensei and Sorami. Shikimi attends the local school with the cleaning club leader Himari and his lively kouhai Shinon. There’s a rumour at the school that the door to another world would be opened by pressing a certain sequence of buttons in the elevator at the lighthouse in the Stargazing Commemorative Hall.

One day, the school committee asked the cleaning club to tidy up the interior of the lighthouse. Together with his mysterious book-reading classmate Misumi, they solved the elevator riddle while doing the cleaning. It led to the top floor of the lighthouse, which was a huge fairytale-like library. This was the other world: Remembrance. A small girl named Amahoshi awoke from her slumber and asked for their help in gathering the town’s scattered memories.