Did you know that dogs don't have much rights that Humans do? They can't go outside for a walk without a leech, and they also can't drink from a water fountain in a park. It's a sad life for a dog. But, for a talking dog who realizes this, it's sadder. Brian is tired of being a second class citizen and wants to be treated with respect, so he decides to break laws and eventually goes to court for this.
I thought this was a great parody of whatever it was probably parodying, this episode being, "it". It was very well written. Brian standing up for his rights, and trying to get dogs like him better rights? Amazing. We get a lot of character development for Brian. In fact, this is probably the first episode all about him, and I thought that was just an amazing episode.
I recommend it. Great addition to the first season of Family Guy!