Hmmm, I was gonna make a fic like this but too many of mine have animal abuse. That aside I think you should have him rescued instead of running away.
What I mean by that is like "dumb" is on the brink of death(and living down in the basement) when the owner's friend comes over and hears whimpering. The owner try's to keep him away from the basesment but the friend gets in anyway and finds the dog.
You could do that and describe when "Dumb" was adopted.
Just a thought if you want to use it your welcome to.
