Tevye is an "ordinary man" (1.2) until he comes into a little money and sets himself up as a dairyman. Well, he's still ordinary. But at least he's not dirt-poor anymore.
Tevye's daughters try to marry according to their wishes, rejecting their village's system of arranging marriages. Surprisingly, Tevye is mostly okay with this radical behavior. He might want to rethink his permissiveness, though, because it ends badly when one daughter runs off with a Gentile and another kills herself after a broken engagement.
The gub'mint forcibly removes Tevye and his family from the village. He leaves thinking that there must be a place where Jews can feel like they belong. Sure there is, Tevye. It's called the Upper West Side.