House Lannister (or: how will a much-discussed prophecy play out?)
Big week for the ruling House. Just in case you've been missing the sexual Queen Cersei since her battles with The Faith, Game of Thrones proudly presents "Queen Doesn't Give Two Poops." Not only does Cersei get cruel revenge on Ellaria Sand with a poisoned same sex kiss that kills the last on-show Sand Snake (presumably she'll be rotting in the dungeon forever), but she beats back the Iron Bank with a sharp Lannister tongue, gives Jaime queenly oral sex, and doesn't care who sees her and her brother in bed. This is a high moment for the Queen, but she has become increasingly unhinged as her power plays pay off. She may not have all Seven Kingdoms under her rule, but she has the best record in Westeros for crushing one's enemies.
Cersei manages to keep the Iron Bank on the side of the Crown for the time being by basically selling the rights to the riches of Highgarden before it's within her power to give those resources (stay tuned next week to see how that turns out). The move pays off fantastically, convincing the Iron Bank to invest in our current Mad Queen over Daenerys. The last time the Iron Bank backed someone from Dragonstone, it ended with Brienne killing Stannis in the woods outside Winterfell. So the Crown does seem like a good investment, even if Cersei's pride and hubris is teetering on the brink of a karmac downfall.
Jaime Lannister, on the other hand (it's a joke!), might slowly come to the realization that his sister is mad… just not this week. Euron's continued cockiness is irking Jaime, even when his sister-lover seems immune to the charms of Emo Rock Iron Born. Plus, Olenna Tyrell's final, forecasting confessions -- that Cersei will lead to Jaime's end -- do look like they weigh on him. As a girl Cersei was told a prophecy that she would die at the hands of her valonqar, the High Valyrian word for "little brother." Book readers suspect the reverse might be true.
Part of the episode description for this week said "Jaime learns from his mistakes," and the reference to the Battle of the Whispering Wood is a reference to how Jaime got himself captured in Season 1. Jaime was heading the Lannister forces laying siege to Riverrun while his father Tywin was trying to hold off Robb Stark's army from reinforcing the Tullys, when a scout reported 20,000 Stark men marching towards Tywin's forces. Thinking that was the bulk of the Stark army, Jaime was lured into the woods outside of Riverrun attacking what he thought to be a Stark scouting party, but which ended up being Robb's army. Robb sacrificed 2,000 men to Tywin's forces while he took Jaime prisoner and ended the Lannister siege of Riverrun. Jaime learns from his mistake by pulling this same trick on Tyrion this episode, leaving a small force at Casterly Rock while taking the Lannister and Tully army to Highgarden instead. So he's not completely off his game.