SOLVED. YA fiction book read 2010-ish, about three mice(?) getting lost in the sewers and finding a city of rats and mice. [s]

[Bee]

I read this book in the early 2010's, the main characters were three mice brothers, who lived in a petshop. I forget exactly how it happens, but the three of them end up escaping the store, or maybe getting thrown out, and then they try to stick together but a rain storm knocks all of them into the gutter where they get swept into a drain, two of them going one way I believe, and the other appearing to get killed. (Maybe stepped on by a human?) So it ends up with at least one of the brothers getting lost in the sewers and finding his way to this big kingdom underneath the streets filled with mice and maybe rats as well, while the other brother, who was thought dead, gets saved by the evil faction, either rats or maybe cats? I forget most of the story from here, but I remember there is a lot of subterfuge plots, and the brother who was presumed dead ends up turning evil I think. One bit that sticks out to me a lot, is that the cat(s?) are described as having like super glowy eyes, and I think there might be some sort of magic in play. The main character mouse also has his part of his ear torn off I remember, it becoming a signature of him, with his left ear having a large torn hole in it. I remember the description of it being torn especially gruesome which I found surprising. I'd really appreciate any help anyone could give me in finding this book, I really loved it when I was younger and I really would like to re-read it!

[Rainbowheart]

The Dark Portal?

[Bee]

Rainbowheart wrote: "The Dark Portal?"

I don't think so, the mice in the book I read were very specifically sheltered, store born mice, who's first entry to the real world lead them directly down the storyline. I found the Dark Portal a few times when looking for this book in the past, and I'm almost positive it isn't the right one.

[Rainbowheart]

Mouseheart?

[Bee]

Rainbowheart wrote: "Mouseheart?"

Oh my gods! Yes that is exactly it, thank you so much!

[Rainbowheart]

Awesome, glad to help out!