So, um, originally, I thought that it would end with Shion dying because of this quote:
When a dog's on its deathbed, suffering, he sings until the dog calms down and stops breathing. His voice carries away their souls...like the wind carries away a flower's petals.
Since a shion is a flower, right? The analogy was just too coincidental.
But then I realized that a flower just losing its petals didn't mean that it would die. It would just have nearly nothing left. And, iirc, Shion had said that if Nezumi died, he would've lost everything, as Nezumi was the most important thing to him; but Shion would still have the Dogkeeper as an acquaintance, so he wouldn't have lost everything... but he would have lost the most precious thing to him. And, well, the petals of a flower are one of the most important parts of it, right? It can survive without them, but not well.
So... my bet is that either Nezumi will die, or he'll leave somehow. Idk if this makes any sense, but they're my thoughts. ^^;