The weirdest power couple in Westeros is Jaime Lannister and Cersei Baratheon, twin brother and sister who have sex with each other. It’s not just a casual thing — they love each other. Their complicated relationship becomes extra-complicated thanks to the events of “Game of Thrones,” however. This is the story of those complications.
When “Game of Thrones” kicked off, Cersei was queen to Robert Baratheon’s king. Jaime, meanwhile, was a member of King Robert’s Kingsguard. As part of the Kingsguard, Jaime was forbidden from marrying or taking an inheritance — convenient for his relationship with Cersei because it meant they were usually near each other.
Unbeknownst to pretty much everyone, Cersei’s children were not fathered by King Robert — Jaime was the real dad. The Hand of the King, Jon Arryn, discovered this, noting that it was a big deal because it meant Robert’s heirs were not actually heirs. Cersei had Jon Arryn killed via poison to hide their secret, and it’s this gambit that kicks off pretty much everything that happens in Westeros from there.
In the series premiere, Jaime and Cersei travel with the king to Winterfell, where Robert recruits Ned Stark to be his new Hand. While there, the child Bran Stark catches Cersei and Jaime hooking up at the top of Winterfell’s tower. Jaime throws Bran out the window, crippling him.
Back in King’s Landing, Ned Stark soon picks up the trail left by Jon Arryn and confronts Cersei about it. She doesn’t deny that her children are Jaime’s. In the North, an assassin is sent to finish off Bran but is foiled by his direwolf. Catelyn knows the Lannisters have it out for House Stark, and kidnaps Tyrion. Jaime fights and wounds Ned, demanding Catelyn free Tyrion. Robert demands they end this conflict, but is killed by a boar on a hunting trip soon after.
Ned attempts to expose Cersei and Jaime, but gets locked up and then executed by the new bastard King Joffrey. Kicking off a four-way, continent-wide war between the Lannisters, Robert’s brothers Stannis and Renly, and Ned’s son Robb, the King in the North. All because of Jaime and Cersei’s incestuous relationship.
Jaime, being known as the best swordsman in the Seven Kingdoms, goes off to war, leaving Cersei behind in King’s Landing as queen mother. Jaime will be captured by the Starks, and it will be years before Cersei and Jaime see each other again. Cersei takes up with her young cousin Lancel in Jaime’s absence, and ruminates on how Joffrey’s insanity is probably her and Jaime’s fault.
Catelyn Stark frees Jaime and charges Brienne of Tarth with returning him to King’s Landing in hopes that the Lannisters will free her daughters Arya and Sansa in kind. Jaime’s journey home is a long one, full of winding detours — and he loses his sword hand along the way. Jaime returns to Cersei broken, with none of the arrogant swagger that had previously defined him. The change threatens his and Cersei’s relationship. Cersei indicates that she may have fallen out of love with Jaime while he was gone.