Ruins Library is a card strategy game, produced and distributed by ProjectMoon. The plot of the game follows the previous work "Brain Leaf Company", and players will play the role of librarians and build their own library strength on the ruins. Players should invite guests who come here to fight together. The winner will take the books he wants, and the loser will turn them into books to expand the library's collection. It takes about 50 hours to complete the whole process of the ruined library.