In a fight with some kind of winged Oni-like creature named Kaa-san, Kaa pelts Kantarou with some kind of thrown feather/quill trick, but Kantarou reflects these back to Kaa. The forms of the feathers change to those of traditional Japanese weapons--a katana, a yari, a tessen, and an arrow, but it is unclear to me which side's magic caused the transformation. To Kantarou's surprise he hits his target, but for whatever reason (perhaps he missed a feather), he realizes he himself has been skewered in the chest by either a tanto or a kitchen knife, it's hard to tell.
I don't have time to scan this immediately, and I'm dictionary dependent to read the context so I can't give you a better interpretation on exactly what is going on.
The volume ends in a cliff-hanger.
(Aside: also, for some reason, a nine-tailed Kitsune is hanging out with Minamoto at the end of the volume.)