David is riding and is intercepted by Ziba, a servant of Mephibosheth, Saul's grandson. Ziba has provisions and asses for David. David asks where his master is, and Ziba informs him he went to Jerusalem in hopes of getting his kingdom back. David tells him he shouldn't steal from his master and rides on.
The next person he encounters is Shimei, another member of Saul's clans. He curses at David and throws stones at him. One of David's men wants to go and punish him, but David is still wallowing in his own misery and refuses. Shimei follows, cursing and hurling stones, as David rides away.
Meanwhile, Absalom is in Jerusalem. One of David's old followers comes to him and offers praise. He asks why he didn't leave with David, and the friend says god has chosen Absalom.
Absalom asks one of his advisors, Ahithophel what to do next. Ahithophel tells him to have sex with his father's concubines, as predicted in chapter 11.
Ahithophel asks Absalom for 12 000 men to pursue David with. That's overkill, isn't it? I mean, David only has 600 men with him and ran away from a guy throwing rocks. Anyway, Ahithophel promises to only kill David and to return his people to the fold. Absalom likes that plan, but wants a second opinion, so he calls on another advisor, Hushai. Hushai thinks he should wait, because David is still pissed off and dangerous. So dangerous he runs from rock-throwers. This is some bad advice, my friends.
Hushai also advises that he should go himself when the time comes and kill everyone with David. Furthermore, if David takes refuge in a city, they should destroy it utterly. Everyone agrees with Hushai, which is all part of god's plan to wreak evil on Absalom.
Hushai tells the priests to send messengers to David and tell him to get himself to a city. A boy sees them and sends word back to Absalom. Poor David has to hid in a well, a la Saddam Hussein in his spider hole. Absalom's servants, oddly less of a crack team than the US Army, fail to find him and move on. David escapes into Jordan, where he is well-received.
Ahithophel, finding his advice isn't followed, goes home and dies, which seems somewhat dramatic.
Absalom follows his father over the Jordan river into Gilead.