Cheng Xiaonuo is an extremely ordinary community librarian. His daily job is to organize bookshelves, help uncles and aunts find health books, and stop naughty children from eating spicy strips in the reading area. Until that day, when she was sorting through donated books, she discovered a bronze key - a key that could open the "door" of any book.
When she opened a copy of "Alice's Adventures in Wonderland" with the key, her whole body was sucked into the pages and came to an infinitely extending library. There are towering bookshelves, endless corridors, books that change positions on their own, and a talking catalog.
Here she meets Qi Xiuyuan, a mysterious man who calls himself the "Keeper of Keys." He told her that the key was the "Master Key", which could open the core area of the Endless Library, and that an organization called the "Chapter Breakers" was hunting down all key holders.
Cheng Xiaonuo's originally peaceful life is completely shattered. While she learns to control the power of the key, she must work with Qi Xiuyuan to prevent the "Chapter Broken Man" from obtaining the most dangerous books in the library - the "original classics" that can rewrite reality.
