Tyrion learns that Bran and Rickon were killed by Theon. Is this really how were are going to learn about a POV character's death? Tyrion is slightly taken aback by the news but otherwise it is all so matter-of-fact.
He goes to give the news to Cersei and have dinner with her. GRRM's menus always sound good. I wonder if anyone has written a cookbook based on them. I bet they have.
Cersei seems nonplussed by the death of Catelyn's kids; she's mainly worried about Jaime and wants to make sure that Sansa is well looked-after. Then she springs her trap on Tyrion: she has captured his prostitute girlfriend! Tyrion is a bit worried about this, but luckily it turns out Cersei has the wrong prostitute. He threatens Tommen to keep Cersei in line and she seems cowed for now. Tyrion realises he's had a bit of a close shave: possibly he will learn some lessons. Hard to say who will get the last laugh.