The little boat is making its way through a foggy part of the river which is the domain of "Stone Men", who are basically lepers but cooler. The meet a friendly boat first, then they get attacked by stone men.
While preparing for that fight, everyone suddenly wants to protect young Griff. With this information and by the colour of his eyes, Tyrion figures out that young Griff is in fact Prince Rheagar's son, previously thought to have been killed by Tywin. Rheagar is Mad King Aerys's son and would have been heir to the throne, except he had an affair or something with Lyanna (Robert's girlfriend) and sparked a rebellion after which Jaime killed Aerys and Tywin and other Lannisters tried to kill all the other children to end the dynasty.
But Varys must have been up to something even way back then to start trying to put Targaryens back on the throne and somehow saved this young prince whose name I have forgotten. He is probably the heir of the throne. He's also Dany's nephew, is that right? That won't stop him marrying her. She might not like giving up the thone, though. Also by Dornish law she might be heir to the throne, so Quentyn could help out there. I have a feeling this could get even more complicated yet...
Oh, and now the boat has been mysteriously turned around and stone men have attacked again and now Tyrion is drowning. After the ad break we'll find out how he gets out of that one.
