Game of Thrones is a story about the rise and fall of houses and with them, the rise and fall of characters. When Season 1 started, House Greyjoy was in the lesser house category, despite their ownership of the Iron Islands, with Theon a ward of the Starks, and Yara off at sea. Since then their fortunes have risen and fallen, with both Theon and Yara having taken the brunt of both. What happened to Yara Greyjoy in Game Of Thrones Season 7? House Greyjoy has fallen on hard times indeed.
Yara is the only daughter of Balon Greyjoy, and with the death of her two older brothers before the series began, the oldest of her generation. Fans didn't meet Yara Greyjoy until the beginning of Season 2 when Theon went home for the first time. It had been so long, Theon didn't recognize Yara, and hit on her before learning who she was. To his horror, his father preferred his sister as the heir to their House over him, despite her gender. Yara isn't very nice about it either, sneering at her brother's plans to take Winterfell, and calling him a fool for angering the Starks.
However, over the course of the seasons, Yara's opinion towards her bratty little brother changed. When Ramsay Bolton captured him, she attempted a rescue over her father's objections, only to discover her tortured and gaslit brother was too paranoid to come with her.
When Theon finally did escape and made his way home again, Yara took him back despite herself. In return, Theon stands for Yara at the Kingsmoot, despite the Ironborn never having a Queen, after their father dies and Uncle Euron returns home to try to claim the Iron Islands for himself. Despite winning over several votes, Yara's bid fails, and the two of them barely escape.
At the beginning of Season 7, Yara has joined with Daenerys, and the two would-be Queens of them have a pact; the Mother of Dragons will help her take back the Iron Islands if Yara helps her take King's Landing. However, on the way back to Dorne, just as Yara was getting to know a Sand Snake or two, Euron attacks and takes her prisoner.
The last time fans saw Yara was Season 7 Episode 3, when Euron walked her through the streets of King's Landing in chains, announcing he was taking his niece to do with as he liked, and Cersei could keep the Sand Snakes. Considering Euron's plan was to kill his rival for the Iron Islands before he attacked Yara's ship, fans have feared the worst for her.
At the end of Season 7, Theon gets word his sister was alive, and takes her loyalists back out to sea, in hopes of a rescue. With Euron off fetching the Golden Company for Cersei, will Theon arrive to find no one home? Or will he be successful in freeing Yara, and taking back his ancestral home? Fans will find out come Game of Thrones Season 8, when it premieres on April 14, 2019.