Y/N was just an ordinary high school girl who loved reading webtoons, novels, and watching anime. But one day, she fell into another world. A world where reality is not normal… but structured like a living story. Everything is divided into “Books”, “Arcs”, and “Events”, as if existence itself is written like a novel. After her arrival, Y/N is bound to a mysterious system known as ECHO VAULT. But this system is different from anything she expected. It does not give easy power. It does not offer safe guidance. Instead, it forces her to survive, adapt, and grow inside deadly “Book Worlds” filled with danger, mysteries, and powerful beings. As she moves through different worlds, Y/N must uncover the truth behind the system, survive impossible situations, and face enemies who may not even be aware they are inside a “story”. But the deeper she goes… the more she realizes something is wrong with reality itself. In a world where everything can be rewritten… Will Y/N remain just a reader? Or will she become something beyond the story?