Jonathan has spent his time since we last saw him composing his Christmas letter to the Romans. He tells the Romans how much he loves them and about how troublesome the neighbours have been. Not that he needs their help! Nope, he has god to help him. Also, he's defeated Numenius, son of Antiochus, and someone named Antipater and he's sending them to the Romans. The Romans' Christmas letter is equally pleasant, like all Christmas letters. A sort of early Facebook, in which everyone's life is hunky-dory and better than yours.
Pretty soon after sending his letter off, Demetrius tries to invade again. He camps nearby, and the army is so intimidated it flees across a river before he can smite them, so he smites the Arabs instead. Simon is having his own adventures, but eventually the two meet again and decide to set up forts. Meanwhile someone else called Tryphon tries to conquer Antiochus, but is afraid Jonathan won't make peace with him, so rather than send envoys he takes the logical step of trying to assassinate Jonathan, which sparks another visit by Jonathan's army. Luckily, he's in a good mood today, so he just wants to exchange gifts. Tryphon manages to lure Jonathan to Ptolemais, where he captures him, then goes to Judea in triumph, which causes the neighbours to invade once again.
Simon is not dead, and he hears about the troubles in Judea. He vows to avenge his brothers and the people elect him new head of the army. He sends a new Jonathan, son of Absalom, possibly the one in Kings, or possibly someone else, to Joppe.
Tryphon has been dawdling in Ptolemais this whole time, but then leaves with Jonathan, intending to invade Judea and finds Simon in charge. He sends word that he'll release Jonathan in exchange for back taxes and two of his children. Simon senses it's a trap but still sends the kids because he worries the people will revolt if they knew he could get Jonathan back but didn't. And of course, he doesn't get Jonathan, so now he's down one brother, two nephews and a hundred silver talents. And Tryphon invades.
His advance guard sends word from the wilderness that they've run out of food, and he tries to send more, but it snows. So he kills Jonathan and goes home to kill the new Antiochus and declare himself king of Asia.
Simon reburies his bones and builds seven pyramids and there's lamentation. Then he keeps going with his infrastructure project, which the bible explains to us in great detail. Then he makes peace with Demetrius in the form of red robes and gold crowns. They win Demetrius over and he forgives them their tax bill and asks them to send some courtiers.
Now there is finally peace, so Simon is declared high priest and the people set about making contracts with each other so they can sue later. But they get bored pretty quickly and invade Gaza. They ask for peace, so rather than murder them horribly, he just banishes them and throws away all their idols. Not dissimilar to modern-day Israel, really. Simon does the same for another group in a tower in Jerusalem. His final act in this chapter is to notice how amazing his son John is and make him an army general. Funny how that works.