Awkward teenager Rintaro is about to close the secondhand bookshop he inherited from his beloved grandfather. But before the bookshop's doors close for good, a talking cat suddenly appears with an unusual request: Rintaro's help. This mission sends them on a cross-dimensional journey to save books from abusive and negligent owners, from a businessman who leaves his books to perish on a shelf to a publishing drone who cares only about bestsellers. The adventures culminate in a final fantastic challenge: a labyrinth that leads Rintaro to a realm where a certain soul hangs in the balance...