Daemon Targaryen's daughter had married Lord Cregan Stark, but after a battle she ended up losing her husband and giving birth to her first child. The girl ends up without a husband and her son no longer has a father, so Rhaenyra saw this as a chance to unite the Targaryen blood of Daemon's firstborn with her heir, Jacaerys Velaryon. Therefore, she and her family travel to Winterfell with the intention of offering condolences and offering a new opportunity for a fulfilling life for the girl.