While outside during school Natsume is hit with a ball while reading. He goes to retrieve the ball and ends up breaking a Youkai's seal (much like he had with Nyanko-sensei). Later that night Natsume and Nyanko-sensei discover a look-a-like of Nyanko, only to have him steal the Book Of Friends!
Stolen Book Of Friends
Melting Into Spring
Youkai Exorcism Amid The Steaming Springs
A Chick Hatches
Tree Of Promise
The Maiden's Circle
That Which You Must Not Call
Emotions Undying
The Man Amidst the Rows of Cherry Trees
Temporary Home
Assembly of Conjurers
The Young Boy in the Empty House