In the time before there was light, there were the dark elves, and they made evil looking red stuff. Mostly because they were upset about the whole newfangled "light" thing, and wanted to turn them all off. Thor's grandpa told them no, killed almost all of them, and locked away the angry red stuff.
Thor's girlfriend finds it.
The last of the dark elves, the 9th doctor, wakes up, and decides to finish what he started those... 10,000? 15,000 years ago? But first he needs the angry red stuff from Jane, who Thor has introduced to mom and dad. The 9th Doctor attacks Asgard, and kills Thor's mom, doesn't get Jane, but gets away. Everyone is sad. Thor offers Loki (locked up in the dungeon) the opportunity to get revenge for the death of their mom. He takes it, and they do, using Jane as bait. Angry red stuff pulled from Jane and into the 9th Doctor. Big fight, Loki dies, Thor defeats the 9th Doctor, and the angry red stuff... gets collected.
Only Loki isn't dead, only impersonating Odin, and the Red Stuff was actually an Infinity Stone!
As Shakespearean as Thor was, Thor 2 takes it down a few notches, letting everyone relax a little into their roles. Darcy and the Intern are great, and poor Dr. Selvig needs some professional help after having Loki fuck with his brain.
There is very little that is bad about this installment of the MCU, but... If any of the movies felt like filler, it's this one. Thankfully it also has one of the shorter running times, clocking in at a lean 112 minutes. I'm very thankful that they didn't feel the need to bulk it out.
Decent, but at the bottom of my MCU rewatch. Again, not because it's bad, but because it just didn't do anything to lift it above anythings that's come before it.
Next Up: Captain America: Winter Soldier!