Oh boy, here we go...
[SPOILERS ALL](#b "First off, the plot line they cut completely. Baelon Greyjoy dies when he falls off one of the bridges at Pyke. Because he doesn't have a clear heir, there's a Kingsmoot/election called by his priest brother Aeron. Yara/Asha runs, as does Baelon's other captain brother Victarion, but his final, crazy and long lost brother Euron shows up suspiciously at the perfect moment and wins by promising the Iron Born to conquer the whole Seven Kingdoms. Now he King of the Iron Islands, he sends most of the Iron Born fleet to invade the Reach (home of the Tyrells) and sends his brother Victarion east to Meereen with a magical horn that is said to be able to bind a dragon. Victarion has other plans though and on the way he runs into a red priest, so now he's worshipping the Drowned God and the Red God and is on a collision course with the navy currently blockading Meereen, because...
In addition to the insurrection of the Sons of the Harpy, Daenerys and company are also under siege by a conventional army, because after she forced Yunkai (the second city in Slaver's Bay she visited) to free their slaves and rode off, Yunkai immediately reenslaved everybody and raised an army to defeat Daenerys. Now that Daenerys has flown the coupe, Ser Barristan Selmy (who never died) is leading the defense of the city, not Tyrion, because...
Tyrion never made it into Meereen to meet Daenerys. After he and Jorah were captured, they were sold into the slave army that is currently besieging Meereen. Also, Tyrion was never travelling with Varys. He was travelling with a group of people lead by Ser John Connington, the best friend of Rhaegar Targaryen. Connington is accompanying Aegon Targaryen, the son of Rhaegar who was believed to be dead but apparently isn't (he may or may not be a fake though). They planned to go to see Danaerys and together they could conquer the Seven Kingdoms, but Tyrion convinces him instead to invade on his own with some mercenaries, which he does. But he's not the only person who's trying to meet Daenerys, because...
Quentyn Martell, Prince of Dorne and son of Doran Martell (he has two sons) is on a mission to Dorne to propose to Daenarys and pledge Dorne's support for her cause. You see, Doran is and always has been a Targaryen loyalist and wants revenge for his brother and sister, he just has more patience than the Sand Snakes. However, when Quentyn arrives at Meereen, Daenerys refuses his proposal and tells him to go home. He doesn't give up though and after Daenerys flies away with Drogon, Quentyn decides to try to tame one of her other dragons. This plan fails, Quentyn is burnt to a crisp and in the process the other dragons escape. Also, the Sand Snakes do not kill Myrcella, because...
Jaime never goes to Dorne to rescue her. There is a plot against Myrcella, but it fails. Instead, Jaime is in the Riverlands, dealing with the loose ends of the war and the fallout of the Red Wedding. He negotiates the surrender of Riverrun, but then has a strange run in with Brienne, because...
Brienne has also been somewhere else. She has been searching for Sansa (not Arya, who everyone still believes is dead) and not finding much until she is captured by the Brotherhood without Banners and brought to their new leader, Lady Stoneheart, who is Catlyn Stark resurrected by Beric Dondarrion. Catlyn/Stoneheart has been killing all the Freys she can get her hands on and when she sees Brienne's sword and finds out she is working for Jaime Lannister, decides Brienne has betrayed her and almost kills her until Brienne convinces her not to and then goes to get Jaime. But it's ok Brienne never went to Winterfell to find Sansa, because...
Sansa never went to Winterfell. She is still in the Vale with Littlefinger pretending to be his bastard daughter. Littlefinger is planning to engage her not to Ramsay Bolton, but to a young man named Harrold Hardyng, who is the heir to the Vale should something happen to young Robert Arryn (who is a very sick boy in the books), and of course Littlefinger plans for something to happen to him. But don't worry about Ramsay Bolton, because...
He gets married instead to "Arya Stark", or at least the girl the Boltons are passing off as Arya to legitimize their rule of the north. Ramsay then tortures her and Reek sexually until they are rescued from the castle by Mance Rayder, who was never burned by Mellisandre. Mellisandre actually cast a spell on the Lord of Bones to make him look like Mance and burned him instead. Ramsay gets very angry about this and sends Jon Snow a letter claiming that he has defeated Stannis in a battle in the snow (this is not shown in the books though) and captured Mance and demanding that his bride and Reek be returned to him. Before Jon can act though, he is attacked by his brothers in a manner very similar to what we just saw.")
I'm sure I left out a bunch of stuff, but that's a pretty good overview of how different this season has been.