AU, from the end of 3x07 in which certain events don't happen and Brienne ends up as the reluctant guest of the Lannisters in King's Landing. (TV universe only, though some details from the books might sneak their way across)

It had taken her quite some time to name her Queensguard. Not to choose them; Sansa had been choosing them for a great deal of time – since the day she watched her father die, in truth – her choices growing and expanding over the years until she’d known with no doubt who would make up her Queensguard before she knew for certain she would be Queen. But a Stark girl ruling Westeros alone was unprecedented enough, even without her unorthodox choice of guard, so Sansa had tread carefully when naming them, choosing her times and her methods with all the canniness she’d learned at the hands of men like Petyr Baelish and women like Cersei Lannister.

Tyrion knew, as he gazed up at the dark skinned Martell man that this was perhaps his only chance to spirit Sansa out of King's Landing and away from his father's greedy fingers. Tywin Lannister would have married the girl himself if he felt he could have gotten away with it, and so Tyrion knew his own marriage was no protection to Ned Stark's daughter whatsoever. "Invite her, demand her, steal her--whatever you choose, Prince Oberyn, choose it soon. Else my lady wife shall break into more pieces than the stars."

He bled out on the snowy grounds of the Night’s Watch, not expecting to wake again. But he did wake, and it was not in the forlorn outreaches of the Wall, but back at Winterfell, where King Robert Baratheon was a day’s ride away… Old Nan had always warned against changing fate, but how can Jon refuse a chance to prevent the game of thrones?

After the death of his brother, Robert Baratheon needs a loyalist Lord on Dragonstone. He also really wants back in Ned's good graces. Or, the Game goes on after the Rebellions. The Starks still won't play, but everyone is playing the Game all around them, and Jon Sand has somehow become an important piece. Robert Baratheon, unknowingly, is the Targaryens' greatest asset.

“You must never reject an alpha’s advances, or they will force them. Or direct them elsewhere and sully your name with whores and bastards,” Alicent explains to him, in the days following Aemond’s first heat at the age of 12. Explaining his added duties, his unexpected new place in society. “After enough times an alpha may let you prepare with oil. But at first you must endure the mating bite, and then the pain of every encounter after.” Or: The world teaches Aemond what it means to be an omega. And then, with much time and healing, his new husband helps him unlearn it.

There is a land of the living and a land of the dead and the bridge is love, the only survival. —Thornton Wilder