King's Landing: We see Littlefinger's co-conspirator, Lady Olenna. I like that she openly wonders why Thrones keeps having her hang out in the the same damn garden every week. She tells Margaery about sneakily seducing a young man who was going to marry her sister when she was a young woman, and brags that she had "very, very good" talents. (Thanks for that image, Thrones.) She tells Margaery, "You are even better;" we hope she's talking about her granddaughter's ability to charm and not about her bedroom skills. How would she even know about them, unless they both took some kind of Westeros standardized sexual debutante SAT test?
Olenna then lets Margaery know she was the one who poisoned Joffrey, and her granddaughter looks stunned and a little wary -- Granny is full of surprises. "You don't think I'd let you marry that beast, do you?"
As many of you guessed last week, the poison was hidden in one of the gems in Sansa's necklace. Littlefinger gave the necklace to Dontos, who gave it to Sansa, who wore it at the wedding. The Queen of Thorns "adjusted" it while talking to Sansa, secretly removed one stone, then presumably dropped it into Joffrey's drink while his back was turned.
Give Thrones credit: They mostly played fair. Clues to the killer's identity were in the episode for those who looked closely enough. Olenna's motive is certainly convincing, and we'll believe Littlefinger will do anything. Plus, the producers had the good sense not to tell us right away, yet didn't drag out the reveal too long either.
But I have quibbles: Why the necklace? Wouldn't it have been far simpler for Olenna to have carried the gem on her? It's not like the stone had an incriminating skull and crossbones on it. The one advantage of having Sansa wear the necklace was that had this plan gone wrong, she could have taken the blame. But that doesn't quite work either, since part of Littlefinger's plan was to snatch Sansa away rather than let her get arrested and examined. So why not use somebody else to carry the poison?
Also, I don't see how Olenna could have gotten the poison into the cup. During her clearest opportunity, the cup was still a few feet away from her on the table. The table was between the royal family and a large audience, so there's a lot of eyes pointed in the direction of the cup, including Joffrey's trained guards. It's hard to imagine Olenna dropping something into the king's drink without at least one person, if not many, seeing what she did.
That said, the killers' identities are dramatically delicious -- Litltlefinger and Olenna, a dark and a light schemer, a wonderful and unexpected combo. (Remember when I pointed out the irony of Olenna's comment to Sansa about how "horrid" it is to kill a king on his wedding day right before he died? Now it's a double-dose irony.)
NEXT: "Knock-knock." "Who's there?" "Boobs!"