A young architect has a dream of building a new apartment building in a poor neighborhood. He believes that he can bring affordable housing to an area desperately in need of it. He's found some investors who are willing to fund him partway, and he's poured in his own life savings to make up the difference. He's even just signed the papers on the perfect empty lot in the perfect empty neighborhood. Now nothing can stand in his way.
Except for the local gang of kids who play baseball there.
They've claimed this lot for their own, and they're not going to let anyone take it away from them. They'll stop at nothing -- legal or illegal -- to keep that property out of the hands of some evil land developer.
I'm thinking that at the end of the movie, the kids win. They always do in this kind of film. Then the family of the ringleader has to move away: his parents couldn't really afford to stay where they were living after his father took that pay cut recently. They were counting on being able to rent a place in that new housing development that was being planned, but when that fell through, they had no choice but to move on to an even worse part of town. Someplace away from all his friends. Someplace away from that old empty lot that they'd saved.
Since the kids win, it's a happy ending!