"House of the Dragon" takes place some 200 years before "Game of Thrones." The Targaryens are at the height of their power, and King Viserys I Targaryen sits the Iron Throne. Controversially, he names his daughter Rhaenyra Targaryen as his heir, which goes against precedent that only a son can inherit. That goes okay for a while, but when Viserys dies and there's a split of opinion over whether Rhaenyra or her younger half-brother Aegon should be the new ruler, all hell breaks loose.
Watch the trailer for HBO's "Game of Thrones" prequel show
We see a lot of that drama hinted at in the trailer. We see several great lords of Westeros swear fealty to a young Rhaenyra, played in her youth by Milly Alcock and as an adult by Emma D'Arcy. We meet the king's second wife Alicent Hightower (Olivia Cooke), who would prefer her son take the throne over Rhaenyra, leading to a bloody rivalry. We also see plenty of King Viserys' violent brother Daemon Targaryen (Matt Smith) and the famed mariner Corlys Velaryon (Steve Toussaint), one of the most powerful lords the day.
And we see dragons. That was nice. There are a ton of them flying around Westeros at this time, so expect the show to be full of the beasts.
Technically, obviously the show looks good, although I note that the photography is very dark; they're picking up where "Game of Thrones" left off. "Game of Thrones" composer Ramin Djawadi is back for more with a pumped-up version of his Targaryen theme from the original show.
"House of the Dragon" premieres on HBO and HBO Max on August 21. Expect the marketing push to get more fierce from here on out.