Remember that smoke baby that Melisandre had? Well, it grew up into a Smoke Stannis that snuck into Renly’s tent and killed him dead, right when he was cutting a deal with Catelyn Stark. So Renly’s out of the picture, which transfers most of his army over to Stannis. The only parts that didn’t defect immediately are those controlled by House Tyrell, specifically Loras and Margaery, both of whom get out of town immediately. As do Catelyn and Brienne, who were the only ones to see the assassination. Brienne is desperate for vengeance against Stannis, but she takes a moment to swear loyalty to Catelyn.
Daenerys gets into Qarth, where she’s swept into a world of delightful garden parties. She does have to take some time convincing the remnants of her Dothraki horde not to steal golden peacocks, but mostly she gets to watch terrible magic tricks and receive marriage proposals from rich merchants. She also discovers that Jorah Mormont is in love with her, because up until now, I guess she assumed he was following her into certain death just for the fun of it. Jorah convinces her not to get married in exchange for a giant pile of money, because he thinks she can conquer Westeros with just one ship.
Now, some quick hits: Bran is still having weird dreams in Winterfell, and he has to send troops to defend against the Mountain and his raids. Theon discovers that the crew of the Sea Bitch doesn’t respect him, and he realizes he should disobery his father’s orders.