Princess Rhaenys Targaryen dies in 'House of the Dragon' season 2 episode 4 'A Dance of Dragons,' and the book 'Fire & Blood' offers more detail.
Rhaenys and Meleys crash through the floor of the dragon pit, interrupting a coronation that had otherwise been going pretty well. Meleys turns on Alicent and Aegon, but Rhaenys does not issue the kill order. Perhaps she is trying to limit bloodshed, or she finds Alicent's protection of ...