When you were quite young, you and your brother got on the wrong side of the Russian mafia. You both split up and went into hiding, and you haven't heard from either your brother or the Russians for several decades. In the meantime, you've gotten married and had several kids, and you've been very successful in your career.
One day, your brother shows up covered in Neo-Nazi tattoos with five chicks he's knocked up and the twenty or so kids he's had between them. He says that he's been one step ahead of the Ruskies ever since you parted company, and he needs some place to hide and money to support his family. You're not thrilled with what he's turned into (and you're more than a little angry that he's probably led the Russian mafia to your family), but he's still your brother, so you're about to offer to let him hide out in the basement and write him a check for a couple thousand dollars. You can afford it.
But before you can do either of those, he pulls a gun on you and demands all your money. You and your family can still live in one of your walk-in closets and he'll give you food, but the house is his. You can't be a Unitarian anymore, and you have to start voting Republican. On the plus side, if the Russians follow him to your home, he'll combine your money with his to fight them off!
Well, this doesn't sound so great, and you're also kind of wondering how he plans to fight off the entire Russian mafia. You're a pretty peaceful guy, but you recognize that not everyone is like you, so you've got a shotgun for home defense. You use it to repulse his initial attempt to take your house by storm, but he shoots a couple of your kids in the process. Then he goes two houses down the block and starts shooting people in there. He takes over their house, fortifies it, and starts using it as a forward base in his attempt to take over your place (which he still wants because it's nicer).
You call the police, but your brother pays them off and tells them that you started the whole thing. They aren't willing to storm your house for him, but they'll give him some of their SWAT team's equipment. You and your next-door neighbor, plus a few survivors from the house your brother took over, get together to fight him off.
It doesn't go so well, and your brother burns down your garage and shoots you and your wife, inflicting massive damage on your house (which I guess he still wants or something?) before your schizophrenic daughter barely drives him off. It's all in her hands now.