Yashio and Mikumo

According to an old saying, all cats may start out with nine lives, but what happens when they begin to use them up? This story enters the secret world of cats, and begins where Yashio gives up one of his own to save Mikumo's life. *Note: Includes the one-shot "Kare to Kanojo no Futoumin (彼と彼女の不冬眠)".*