Take the end of this week's episode, "Walk of Punishment," for example. And it's at this point that you really want to stop reading now if you aren't caught up through Episode 3 of Season 3 of Game of Thrones!
At the end of "Walk of Punishment," just when it was looking like Jaime Lannister had managed to talk his way out of a bit of discomfort, we saw that he'd actually set himself up to be handed an even worse situation. I am, of course, referring to the loss of his hand. The episode cut off (sorry) just after Jaime's hand was severed from the rest of his body. From what I hear, this marks a pretty big turning point for this character. Given that he can no longer wield a sword - right handed, anyway - I'd say that's probably true.
The above teaser for "And Now his Watch Is Ended" gives us a look at some exciting developments, including what appears to be another very dangerous moment for Sam, as well as a look at Cersei's next move. But there's no sign of Jaime, which might mean we won't get to see how he's doing since parting ways with his hand. We do get a look at Daenerys, as she hands over one of her dragons in exchange for an army of men, every one of which has killed a baby. Her willingness to hand over one of her precious dragons shows just how serious she is about this war. She needs an army and her dragons aren't grown enough to be of use to her yet. But is she really willing to let one of them go? It's looking that way.