We're two episodes into "House of the Dragon" and we're up to speed on most of the cast. There's Rhaenrya Targaryen, the heir to the Iron Throne; her father King Viserys and her uncle Daemon. Then there's Corlys Velaryon, the king's master of ships; the richest lord in Westeros, he controls a huge navy and has money coming in from trade along the Narrow Sea.
At least, he did. In the first two episodes, he petitions the king to let him sail his navy to the Stepstones, a series of islands in the Narrow Sea, and take care of a guy named Craghas Drahar, aka the Crabfeeder. This guy is a prince admiral from the free city of Myr. After defeating pirates in the Stepstones (a move the lords of Westeros once cheered) he's set up shop there and is charging egregiously high tolls for ships to pass through. It's becoming a problem.
Myr has teamed up with the free cities of Lys and Tyrosh to form the Triarchy, an alliance that gives them a better foothold against the other free cities, and against Westeros. The Triarchy is supporting the Crabfeeder's campaign in the Stepstones, and Corlys Velaryon has had enough.
"House of the Dragon": Who is Craghas Drahar the Crabfeeder?
The Crabfeeder earned his nickname because of the way he deals with those he defeats in battle: he fixes them to posts and lets them be drowned by the incoming tides. The crabs have eaten well lately.
At the end of "The Rogue Prince," after the king had yet again denied Corlys leave to attack the Crabfeeder for fear of starting a war with the free cities, the head of House Velaryon sought out the help of Daemon Targaryen, who's looking for a way to get back in good with his older brother the king. The two are off to war! We'll see how that goes in future episodes.