Chapter 47 has Yukino, Tohno, Mei Mei, and random others searching for kappas, combined with intermittent flashbacks by Tohno about an old monk she used to know. To be honest, I don't know why it's numbered rather than a side story. Character background information for a character that I like is always good, but you're more about the romance right? Well, it goes back to more, as in less, serious stuff in the next chapter anyway.