During parts of Sunday's fourth episode of Game of Thrones, titled "The Last of the Starks," Winterfell ostensibly turned into a frat house. Spoilers ahead for Season 8 of Game of Thrones. And while it was a deserved celebration after Arya killed the Night King, it also presented the perfect setting for the long-awaited — yet still highly surprising — Brienne of Tarth and Jaime Lannister hookup. It seems like Jaime was fully committed to leaving his past behind him, until the end of the episode when he leaves Winterfell to head south. So uh, why is Jaime going to King's Landing? He and Brienne have such a good thing going.
Well, in short, sh*t's about to go down in King's Landing, so Jaime feels like he needs to be there for his sister, Cersei, even though Brienne clearly explains that he could easily stay in Winterfell to stick with the northern army. Seeing as a giant war between Daenerys and Cersei is most likely about to break out — it already began in Episode 4, when Daenerys led her armies to King's Landing — it seems likely that everyone will make their way to King's Landing in the near future, but Jaime had the opportunity to stay safe and sound in Winterfell with his new love. Instead, he left for King's Landing in the middle of the night, seemingly desperate to get there before it's too late.
In explaining to Brienne why he needs to rush down to King's Landing to be with his sister, Jaime insisted that he, at his core, hasn't actually changed, despite the fact that Brienne sees a good side to him. Jaime argued that he had already shed so much blood just for Cersei that he feels he can't turn his back on her now. "She's hateful, and so am I," the Kingslayer said before hopping on his horse and riding away, leaving Brienne uncharacteristically distraught.
Jaime makes it seem like he needs to go to King's Landing because of old habits. He's killed for Cersei before, done everything humanly possible to make his way back to her, and his speech to Brienne could be interpreted as his own acceptance. He accepts his previous nature, and thinks that's the only thing he can do — go back to Cersei. That said, it's also possible that Jaime doesn't mean that at all.
Earlier in the episode, Sansa all but declared that Cersei's about to die when she told him, "I always wanted to be there when they execute your sister," while relaying the news that Cersei's army killed Daenerys' dragon, Rhaegal. It's possible that hearing of his sister's seemingly impending doom inspired him to make one last effort to appeal to any goodness she may have in her, to get her to stop this war before it starts.
His farewell speech to Brienne might suggest that he's going to King's Landing to save his sister, but the fact that he left Cersei at the end of Season 7 to join Winterfell's army might suggest that Jaime just wants to say a final goodbye before his sister is killed by the Queen of Dragon's wrathful vengeance.
There's even a popular Reddit theory that Jaime will actually kill Cersei, which could be the ultimate romantic gesture to win over Brienne.
If these fan theories are right, Season 8 of Game of Thrones could continue to reveal surprising triumphs against the series' most evil leaders, and that might just include Jaime's redemption.