Chapter 31 (Catelyn III):
Chapter 32 (Sansa III): Well, since Cat and Robb have been separated by a goodly distance, and Theon is no longer part of Robb's army, we aren't going to see what's going on with Robb's fight ourselves for a while. So we have to hear of the latest Stark battle secondhand through Sansa's ears. Joff is mad about the beating Ser Stafford's army has taken, including Stafford's death. He has a pretty strange idea of how the battle went, though, saying Robb hit them with a whole army of warg direwolves.(I'm guessing wargs are along the lines of what Bran has been doing with Summer in his dreams.) So Joff decides Sansa must have a beating in exchange as punishment for her brother's victory. Oh yeah, Joff is scum. Good thing Tyrion shows up to stop it before it gets really bad. Sansa could have been hurt a lot worse if he hadn't come in right then. Tyrion has his men bring her to the Tower of the Hand and clean her up, and then give her a potion to sleep. In Arya's old bedroom, by coincidence. Afterwards he tells her a truer-sounding story of the battle, and offers to keep her here for her safety. She decides she'd rather have the chance at escape with Dontos, and asks to return to her old chambers. Oh yeah, Joff is scum.
Chapter 33 (Catelyn IV): So Cat goes to pray, and reflects on Stannis's claim about Joff. It makes sense to her, and she figures this is why Bran was pushed out a window. She returns to Renly's tent, where he is consulting with his lords while Brienne is dressing him in armor. They want him to attack right away, but Renly wants to wait till dawn, being honorable because it was the chosen hour. Never mind he would have his forces, those he brought with him, heading into the sunrise. Renly isn't much of a strategist. Renly orders that is Barristan is fighting alongside Stannis, to allow him to live. Except he isn't with Stannis either, we know this from Davos's chapters. Whenever Barristan shows up, he has some explaining to do as to what he's been up to all this time. None of Renly's orders matter, though, cause a gust of wind blows the door open... and a shadow walks in without an owner. Cat thinks it's Renly's shadow at first, but by the time she figures it out, it's too late. The shadow drives a shadow sword into Renly's neck (through his armor) and kills him. Brienne screams, and two of the Guard burst in and assume she did it. Cat has to plead for her life, and gets her away, sure that Stannis is somehow responsible. The Stark party flees, knowing that Renly's forces will go over to Stannis. So much for Renly having the bigger army.