Ever since we learned (or, let's be real, fervently began speculating that) Jon Snow is a secret Targaryen with more information than anyone about how to defeat White Walkers, Game of Thrones fans have been eagerly awaiting the meeting of "Ice and Fire" — Jon and Daenerys. While it wouldn't be unheard of in the Game of Thrones universe for an aunt to fall in love with her nephew, the idea of a romantic pairing has largely fallen by the wayside since we learned they were related. But Daenerys and Jon Snow met on Game of Thrones in Season 7's third episode, "The Queen's Justice," and the reactions were just as explosive as you'd imagine.
Daenerys sent a raven to the King of the North via Tyrion earlier this season, demanding that he bend a knee to the rightful Queen of the Seven Kingdoms. He's understandably wary of her, considering that earlier Targ rulers have laid similar traps teasing alliance only to kill people who threaten their power. But Dany has something Jon needs — her ancestral seat at Dragonstone sits atop a mine of dragonglass, which is the only known substance that can be fashioned into a weapon to destroy the White Walkers and their wight army. (Fire breathing dragons also do the trick.) So he goes, leaving Sansa in charge of the North, and, needless to say, Dany and Jon's meeting blew fans away.
The exchange was pretty brilliant, if somewhat frustrating in the end. Dany obviously demanded that Jon bend a knee and pledge fealty to her in her personal war against Cersei. Jon, meanwhile, was simply trying to convince everyone that uh, White Walkers are coming and literally nothing else matters. She didn't exactly believe him, as Tyrion later pointed out to Jon, for good reason. "She's not about to head north to fight an enemy she's never seen with a man she doesn't know after a single meeting," says the imp to the King in the North. "That's not a reasonable thing to ask."
Actually, how little Jon and Dany know each other was a big theme of this scene. The two rulers were initially introduced to each other by their advisors, Missandei and Ser Davos. Missandei rattled off Daenerys' long list of titles in a tone meant to underscore Who Is In Charge Here, while Ser Davos, apparently caught off guard by a basic part of his job description, presented his boss as a bastard and, um, King of the North. (I also would have thrown in Former Commander of the Night's Watch, but hey, he hit the essentials.)
Davos later redeemed himself by standing up for Jon, but Jon's ultimate refusal to pledge himself to Daenerys in their first meeting didn't turn out well. Dany took Jon's weapons and his ships just before receiving news of Euron's attack, at which point, she basically put him on the back burner. Once Tyrion works his rhetorical magic, Jon understands that the best he can hope to walk away with is what he came to Dragonstone for in the first place. He asks to mine the stores of dragonglass, and Tyrion manages to sell Daenerys on this, pointing out that Jon will owe them a favor in the end. She agrees and it seems like, for now, there's a cautious understanding between the two, although it isn't exactly an alliance just yet.