Sansa goes up to the tower to look through the smoke for signs of Stannis' approaching army. She gets hassled by the Hound again. Then she visits Dontos in the godswood, who is drunk and wants a kiss. And also isn't going to be able to get her out of the city for ages. Probably until after the war, if you ask me. We also learn that there are limits to what Stannis can achieve by land because of the river and he could really do with more ships which won't arrive for a long time.
Then Sansa goes to bed, has terrible dreams, and wakes up to discover she's had her first "flowering". She tries to burn the evidence but gets caught in the act. Interestingly she pretends to Cersei to be more naive than she really is, claiming she was scared of the blood and expected it to be more magical, when in fact she's just scared of having to marry Joffrey. Cersei seems to buy that line, even if she sees straight through the lie that Sansa loves Joffrey with all her heart.
What if Sansa is going to get smarter without anyone noticing, and then take them all by surprise later on? Another clue to this might be Dontos pointing out that nobody pays lady Tanda's daughter any attention because she is too stupid. For that matter, is Tanda's daughter up to something?
Addendum: when Sansa got blood in the sink, she realised the maid would see it and her secret would be given away. She couldn't empty the sink because she doesn't have indoor plumbing. Let that sink in (yes, I know). She's the 1%; the nobility; and she doesn't have plumbing. That's how impoverished Westeros is.
