God tells Isaiah to pick up a pen and a pad of paper, because he's going to tell him about Mahershalalhashbaz. Then he has sex with a prophetess, who gets pregnant and has a son called, wait for it, Mahershalalhashbaz. I know, I know, you were all thinking the name would be Immanuel. What was the pen for, exactly?
Before the kid is able to talk, all the spoils of last chapter's war will be taken away by the king of Assyria, because the Israelites have been bad. Then he tells the foreigners to be afraid, because he's going to crush them, so they'd better convert now. God will keep talking to Isaiah, because his family are meant to be a warning to the people of Judah. Nope, it doesn't make a whole lot of sense, but they can't edit it out.
The darkness and despair will not last forever. I reckon a year or so, until I finish this book. But Isaiah is talking about his messiah, who will free the people and vanquish their enemies and peace will be upon the land.
The leaders who lead the Israelites astray will be killed, along with the wives and children of hypocrites. So everybody, then. Who will do the killing? Not god, men. They'll even kill their own brothers. They will also become ravenously hungry, so much so that they eat their own arms. Or children, depending how you want to interpret it. Then all the Israelite tribes will turn on each other.