Demetrius is born in Rome, but heads to the sea coast with some men to set himself up as ruler. He enters a palace his ancestors occupied and discovers that his army has brought him Antiochus and Lysias, but he isn't really interested in them, so they are killed. Only then is Demetrius crowned. And then all the wicked people of Israel come out of the woodwork.
First is someone called Alcimus, who wants to be high priest and wants to get there by spreading vicious gossip about his rivals, in this case Judas. He asks Demetrius to send an army to conquer Judas once and for all. He selects his friend Bacchides and sends him to Jerusalem with Alcimus.
This time is a little different, because Alcimus is a priest. People who don't agree with the Maccabees start joining him and he promises not to hurt them, then has seventy of them killed for heresy. Then he just leaves there bodies sitting out and everyone's too afraid to bury them. Then they go to a town called Bezeth with a bunch of prisoners, who they also kill and throw into a pit. At this point Baccides feels like his job is done, so he goes back to Demetrius, leaving Alcimus in charge.
Alcimus is still clinging to his dream of becoming high priest, and of course all the other terrible people start following him, which finally gets Judas' attention. So Judas goes and kills a bunch of the 'traitors.' Still not sure how anyone's a hero here.
Alcimus sees he can't win, so he goes crying to Demetrius again about all the ways Judas is hurting his feelings. This time, Demetrius sends a raging anti-Semite prince named Nicanor back with Alcimus. He sends a friendly letter of peace to Judas, who agrees to meet with him, but really he's planning to kidnap him. Judas hears of the plot and doesn't show. So Nicanor attacks him and loses 5000 men. The rest go to Jerusalem.
Nicanor himself heads up Mount Sion and the priests show him the burnt offerings they've been making in the king's name. He makes fun of them and says he'll burn the place down if no one brings him Judas' head on a platter. This makes the priests cry, and they pray to god to let Judas defeat Nicanor and his army for his blasphemy.
Nicanor sets up camp and so does Judas. Judas prays to god to avenge the blasphemers. Nicanor is killed in the battle and his army flees. The Israelites chase after them for a day, then kill them all. They hang Nicanor's head and right hand on the city walls, which causes the people to rejoice and declare the day a holiday.