The second prequel spin-off of Game of Thrones, titled A Night of the Seven Kingdoms, is set in the year 209 AC, approximately 90 years before the events of the original series. This places it in the timeline between the main series and the first prequel, House of the Dragon, which itself is set 200 years prior to Game of Thrones. A Night of the Seven Kingdoms will explore a distinct era of Westeros during the reign of King Daron II Targaryen, a time when dragons are extinct, but the Targaryens continue to rule the realm.
The series is based on George R.R. Martin's three-part novella series 'Dunk and Egg', beginning with 'The Hedge Knight'. It follows Sir Duncan the Tall, known as Dunk, and his squire Egg, who is later unveiled as Aegon V Targaryen, a future king of Westeros. Their tale starts at a tournament in Ashford where Dunk meets Egg, a disguised stable boy. Following a perilous encounter with Prince Arion Targaryen, Egg's identity is uncovered, leading him back to his family and choosing Dunk as his knight.
As their journey unfolds, Dunk becomes a legendary figure noted for his size and heroism, and Egg grows into a wise ruler, eventually inheriting the Iron Throne as King Aegon V. HBO plans to adapt the subsequent novellas, 'The Sworn Sword' and 'The Mystery Knight', into future seasons of A Night of the Seven Kingdoms.
Their story culminates in the tragedy of Summerhall in 259 AC, a mysterious fire incident. Game of Thrones begins roughly 40 years after this event. Egg's lineage includes Jaehaerys II and his grandson Aerys II, otherwise known as the Mad King, whose death occurs during Robert's Rebellion and leaves his children Daenerys and Rhaegar, prominent figures in the original series.
This new series will not only highlight Dunk and Egg's adventures but also fill in the backstory of significant House Targaryen figures, connecting pivotal events in Westeros' history. Notably, Dunk shares qualities with Game of Thrones characters like Brienne of Tarth and Jon Snow.