Daemon Targaryen's reference to Harrenhal's strength in House of the Dragon's season 1 finale sets up his major storyline in season 2 and beyond.

WARNING! This article contains SPOILERS for House of the Dragon's season 1 finale and George R.R. Martin's book, Fire & Blood!

Daemon Targaryen teases his next big story in House of the Dragon season 2 when mentioning the significance of Harrenhal. Much more than in Game of Thrones, Harrenhal has already played a significant role in House of the Dragon. Not only is it the hold of House Strong and the location where Harwin and Lyonel were murdered, but its geography will play a key role in the political strategy of House of the Dragon’s Targaryen civil war. Daemon Targaryen says as much in House of the Dragon’s season 1 finale, where he mentions that Harrenhal is the ideal gathering location for the Black army’s host.

However, the Blacks don’t hold Harrenhal yet in House of the Dragon, as the “cursed” castle is under the control of House Strong. While Ser Harwin Strong was the real father of Rhaenyra’s sons Jacaerys, Lucerys, and Joffrey Velaryon, Harrenhal is now in the possession of Harwin’s murderous brother Lord Larys Strong, who is a powerful member of Alicent's Green party. As such, Daemon’s major storyline in House of the Dragon season 2 is set up to follow his assault on Harrenhal, capture of the castle, and campaign to band together the Riverlands against the Greens in support of Queen Rhaenyra’s cause.