George R.R. Martin’s The Winds of Winter is set to repeat Red Wedding, which is known as Game of Thrones' most shocking moment, the series features one gut-wrenching death that not even the most cynical of viewers can downplay: Shireen Baratheon's sacrifice. The kind young daughter of Stannis Baratheon was chosen by Melisandre to be burned alive as a sacrifice to the Lord of Light with her parents' approval – a moment that will be tragically relived in The Winds of Winter.
When Game of Thrones producers David Benioff and D.B. Weiss were preparing for storylines that had sured George R.R. Martin’s A Song of Ice and Fire novels, the two arranged a meeting with the author to glean information about the important moments that had yet to be revealed. Martin gave them three “holy sh*t” moments: Hodor’s “Hold the Door” origin, Shireen Baratheon being burned alive, and Bran becoming King of Westeros. Martin revealed that Shireen’s death is planned for his book The Winds of Winter, though the circumstances will inevitably deviate from Game of Thrones’ depiction.
The effect of Shireen Baratheon’s death in The Winds of Winter will seemingly be changed in a few significant ways based on the character being in very different places in the show and book. Shireen Baratheon’s death in Game of Thrones occurred when she was traveling with Stannis’ army to Winterfell, whereas Shireen was left back at Castle Black with Jon Snow while Stannis set off for his attack in the books. As such, Shireen Baratheon’s tragic death isn’t apt to be a sacrifice used to help the army a blizzard on their way to Winterfell. This means that, while concrete details are clearly unavailable, it's inevitable that the circumstances around Shireen's death will need to change.
While GRRM’s comments haven’t specified that Stannis will give the order for death, it’s highly unlikely that Melisandre would sacrifice her without Stannis being present. As such, her death likely won’t occur until Stannis takes Winterfell and he sends for them or if his army must retreat back to Castle Black. If Melisandre does choose to burn Shireen back at Castle Black on her own, The Winds of Winter would still have to make it a desperate matter, perhaps as a way to find Azor Ahai if Stannis dies, to resurrect Jon Snow, or to defend the Wall, with her actions also leading Stannis' official disillusionment with the Red Priestess.
Since Shireen likely won’t be sacrificed as a way to help Stannis’ army approach Winterfell, The Winds of Winter may see her death occur as a way to fight the Others back at the Wall. The wights are quickly approaching the Wall as The Winds of Winter kicks off, so Melisandre and Stannis may see that sacrificing Shireen due to her king’s blood will be the only way to ensure that Stannis’ army can face the undead creatures. Just as Game of Thrones' Stannis claimed to “hate” that he had to sacrifice his daughter in order to follow his fate, GRRM's The Winds of Winter is apt to see her death as a desperate last-minute resort, especially since he has just declared that if he dies in battle, he wants Shireen to be put on the Iron Throne.
Shireen’s sacrifice will be a much more desperate matter to save humanity in The Winds of Winter, as Game of Thrones’ sacrifice of Shireen was simply advised by Melisandre to increase Stannis’ chances of ending up on the Iron Throne. Since Game of Thrones also introduced Shireen’s dynamics with Ser Davos as a way to become far more connected to the character before her death, The Winds of Winter is apt to build up her relationship with Stannis more substantially in order to increase the emotional stakes before the tragic decision is made. The death of Shireen is the beginning of the end for Stannis in Game of Thrones, but The Winds of Winter will likely see a much more morally conflicted sacrifice, which will inevitably still end in Stannis’ downfall.