After Natsume returned Amana’s name, she accused him of stealing her ring.  He has three days to find and return it before she burns down his house.  To make matters worse, the ring is trapped in the hair of a migratory youkai, and Nyanko-sensei is unable to use his powers.
A youkai after the Book of Friends?
¿Será algún youkai que 
vino por el Libro de los Amigos?
¿O quizá un youkai que venía a por el libro de los amigos?
Um youkai procurando o Livro?