Cersei is having Tommen sent with Lord Gyles to Lord Gyles' castle, so Tyrion plans to intercept him and have Jacelyn Bywater take him there instead, and take over the castle as well. To what end, I have no idea.
Tyrion is getting careless and is far too in love with his prostitute, Shae. He plans to hide her in the kitchens in the castle because it's safer than her manse. I'm not sure he should keep her so close seeing how he loses 50 IQ points when she's nearby. She's a bit miffed at the idea of having to do actual work; I'm not sure long she'll stick around for that. At least Varys has the better idea of giving her a better station, as Lollys' maid.
Tyrion also learns that Penrose is dead and Varys uses some Scooby Doo logic to figure out that Stannis is using magic. We also get the awful back story of how Varys became a eunuch. I almost feel sorry for him, as does Tyrion. He is awfully clever, though. He seems to have figured out Edumure's plan to trap Tywin. Littlefinger is still missing; he must be up to something.