Lord Karstark has murdered a couple of squires in revenge for his sons killed in a battle. This is so obviously unfair that Robb has no choice but to put him to death. By his own hand, of course. Which means that Robb has lost some more friends and made some more enemies. One of the squires was a Frey, so that will just add insult to the injury of spurning Frey's one of daughter Frey's. The main thing we learn here is that Robb is just like his father: he doesn't like what he must do, but he does what he must do.
His wife Jeyne goes to Catelyn for advice about Robb's sulking. Just leave him alone until he snaps out of it. Oh, by the way, an heir will be useful. Not to worry, the mother-in-law is giving Jeyne some concoction to make her fertile. What are the chances there is some skulduggery there?
