While looking for her cat, Kansuke, Yumi lands smack-dab in the middle of a mystery! Cats all over Matabi Academy have been disappearing . . . so Yumi decides to play detective and investigate. Unbeknownst to her and the student council, however, is that the demon cat Kaen's disciples have infiltrated the school in human guise in an attempt to steal the school founder's secrets! And when Yumi's investigation leads her to the heart of those secrets-the old library-she and two student council members find themselves trapped in Rachi the sickle spider's web . . . with none of their cat partners anywhere to be found! Will Kansuke, Sakura, and Raimu make it in the nick of time to save their friends?