Dany and her special advisors kick off their plan to take over the Iron Throne in the second episode of the seventh season. She was meeting with Daenerys, Yara Greyjoy, and Ellaria Sand, deciding how to use their combined forces. Casterly Rock, for example, has been the topic of quite a few conversations in past seasons, though viewers have yet to be introduced to the location. We see Euron parading through the streets of King's Landing with, what we must assume, is his gift for Cersei.
Later, she meets Melisandre, who talks about Jon Snow, and advises Daenerys to make an alliance with him. Meanwhile, Cersei's mad scientist developed a new and experimental method of killing dragons: shooting them with a crossbow! Grey Worm tried to turn down the moment, twice, and Missandei wasn't here for it. They're as good as dead if you ask me. That being said, who knows how valuable Sam's (John Bradley) work is in the Citadel, and what it would mean if he can cure Jorah's (Iain Glen) Greyscale, but I hope it's worth the pain. Which is why she was so surprised when Hot Pie told her that Jon Snow is now King of the North. It'll be hard to see her being the one to successfully finish off Cersei, given just how much the show has been hinting at the inevitable bloody confrontation between Cersei and Jaime. She implores Nymeria to come back to Winterfell with her, but instead Nymeria simply walks off with her pack. We see his boat landing at Dragonstone (we wonder if Ser Davos will relive his merry times with Stannis Baratheon as he accompanies Jon for his meet-and-greet) and then Tyrion leads them up the long walkway, all the way up to the throne room - where Dany awaits.
In the episode "Stormborn", we see the childhood companions together again, if for only a moment.
He also receives a letter from Sammy, alerting him about the dragonglass in Dragonstone. Dany and Jon coming face-to-face for the very first time.
While he is away, he hands over the North to a reliable hand - Sansa Stark. "Everyone is your friend", Littlefinger says in the clip as quoted by Refinery 29. He captures Yara and Ellaria, and, as far as we can tell, kills two of the Sand Snakes - hanging and mounting them on the bow of Yara's ship - and takes their whip as proof, or simply a souvenir. And, oh yeah, the moment where Arya discovered that Jon Snow had become the King of the North was pretty emotional as well.