In a show featuring an ensemble cast of literally hundreds of characters, Game Of Thrones' main protagonists seem to be Jon Snow and Daenerys Targaryen. We've followed their adventures more closely than any other character. Those paths have not crossed, however...until this season.
The King in the North and The Mother of Dragons finally met in the seventh season of the show. Fans have been awaiting this for years. As the season progressed, we've seen a potential budding love interest grow between them.
Rhaegar Targaryen was prince of Westeros and first in line to the Iron Throne. He's actually just as responsible for the fall of the Targaryen household as his insane father. It's a bit of a complicated story, but here it goes in the simplest manner possible.
Rhaegar was married to Elia Martell ("The Viper" Oberyn's sister). They had two children together, but due to complications with the birth of their last child, Elia wouldn't be able to bear any more. This deeply upset Rhaegar.
You see, Rhaegar was obsessed with a prophecy about an ancient hero that he thought would return through one of his children. Since he couldn't have any more with his wife, he searched for another woman to bear them. Enter Lyanna Stark, Ned's sister.
Lyanna was betrothed to Robert Baratheon (the king at the beginning of the TV series), so this started the war that lead to the Mad King's fall. It was all over Rhaegar taking Lyanna against her will. This is what everyone thought, until recent events confirmed otherwise.
Jon Snow is actually the (not bastard) son of Lyanna and Rhaegar. He never got to meet his parents, because Rhaegar was killed by Robert Baratheon and Lyanna died during childbirth. Ned got to his sister just in time before she passed away.
As she died, Lyanna whispered something in Ned's ear. She likely asked him to take care of her son. Ned pretended to be the boy's father, as Robert Baratheon would have been so angry that he may have killed the infant Jon Snow.
So, for those of you keeping score, Jon is the son of Dany's brother, which means Dany is his Aunt. So yeah... those googly eyes they've been giving each other feel mighty weird all of a sudden, don't they? Hey, incest runs in the Targaryen family, so at least there's history with this sort of thing. Doesn't make me feel any less dirty watching this go down, though.