During the war with Nebuchadnezzar, God sends his word to Jeremiah.
He tells him to go to King Zedekiah and tell him that God's going to burn down the city and kill everyone.
Zedekiah himself will be captured, but he won't die in the fighting. He'll die in peace and people will at least lament his passing. That's the good news.
Jeremiah tells all this to Zedekiah.
Jeremiah/the narrator notes that Lachish and Azekah were the only fortified cities the Babylonians hadn't defeated yet.
Zedekiah makes a proclamation telling everyone to free their Hebrew slaves. They all obey at first, but afterwards people begin to re-enslave the slaves they'd just freed.
God speaks to Jeremiah, and tells him that the people are again violating their covenant with him. When he led them out of Egypt, he'd told them they needed to free their Hebrew slaves but now they're refusing.
Even with the Babylonian army on their doorstep, the people keep disobeying. Maybe they need their slaves to pack for the trip.
Anyway, look out, slave owners. God's going to punish you with war, disease, and famine.
The people who took back their slaves will end up being like a calf cut into pieces.
Everyone's going to be either captured or made into food for wild animals and scavengers.
King Zedekiah and his officials will be captured, and the Babylonians will capture and burn Jerusalem and all the towns in Judah.