Season 4
1. After being killed at the Red Wedding, Catelyn Stark becomes an undead creature and joins a group of mercenaries called the Brotherhood without Banners.
2. Arya Stark takes a boat to Braavos, where she assumes the identity Cat of the Canals and trains to become an assassin.
3. King Joffrey and Margaery Tyrell have a wedding, but during the feast, Joffrey chokes and dies. Cersei Lannister blames Tyrion Lannister and throws him in jail. (It was actually Littlefinger and the Tyrells who killed Joffrey.)
4. Tyrion escapes prison with help from Jaime. He finds Shae in his father's bed and strangles her to death. Then he shoots his father with a crossbow while he's on the toilet.
5. Littlefinger abducts Sansa Stark, claiming her as his bastard daughter, and takes her to the Eyrie, where he woos Lysa Arryn and marries her.
6. Lysa Arryn catches Littlefinger kissing Sansa Stark. Before Lysa can say anything, Littlefinger throws her out a door and kills her.
7. While traveling to the Wall, Bran and Hodor encounter what appears to be a benevolent wight named Coldhands who accompanies them to the North.
8. The wildlings attack the Wall. Jon Snow commands the forces that drive them back. Ygritte is killed during the battle.
9. Daenerys Targaryen settles down in Meereen and becomes queen, confining two of her three dragons in a pit. Snooze.
Season 5
10. Brienne travels to the Riverlands to find Sansa Stark. Instead, she finds the undead Catelyn Stark (now called Lady Stoneheart), and she is hanged.
11. Samwell Tarly leaves the Wall to study to become a Maester at the Citadel. We meet a new character named Pate, who is promptly poisoned. The poisoner assumes Pate's identity and greets Sam when he arrives at the Citadel.
Season 6
12. Jon Snow is elected Lord Commander. He lets the wildlings through the Wall and conscripts them into the Night's Watch.
13. Jon Snow plans to leave the Wall to defend Winterfell from the Boltons and Lannisters. As he's leaving, he is betrayed by his fellow Crows and is stabbed several times and (presumably) dies.
14. Bran and Hodor make it to the North and meet a magical tree-man who gives Bran access to the memories of all the weirwood tries in all of Westeros, which are pretty much just a network of surveillance cameras.
15. Jorah Mormont finds and captures Tyrion, and intends to give him to Daenerys Targaryen, but Tyrion escapes. Tyrion is immediately captured by slavers, who force him to become a dwarf jester.
16. We're introduced to a new character named Reek, who is Ramsay Bolton's lap dog. It's actually Theon Greyjoy, who has become disfigured and insane after years of torture.
17. Cersei is forced to walk through King's Landing naked to atone for her sins. She still needs to answer for her crimes, so she gets help from Master Qyburn, who creates a mute, 8-foot, monster creature named Robert Strong to act as her bodyguard and champion.
18. Tyrion escapes servitude, and finds another living Targaryen named Aegon, who has a better claim to the Iron Throne than Daenerys. Tyrion convinces Aegon Targaryen to assemble an army and declare war on the Seven Kingdoms.
