- In outer space, a group of not-especially-nice-looking aliens—the Chitauri—discuss the Tesseract, which has been found on our teeny tiny little planet Earth, and which the aliens' unnamed ally will get back for them.
- Hideous alien invaders will follow in short order.
- Meanwhile, at a hidden SHIELD base (SHIELD being Marvel's government organization basically in charge of keeping Earth from being gobbled up by the weird), Nick Fury (Samuel L. Jackson) oversees an evacuation.
- Why are they evacuating? Down in the basement, Dr. Eric Selvig is poking at the all-powerful Tesseract in handy cube form. Nothing can go wrong here!
- And…something goes wrong, though from an outside source instead of from here.
- The Tesseract activates, opening a door across the universe for the god Loki (Tom Hiddleston) to strut on in.
- Loki has a magic staff that turns anyone he touches with it into his personal zombots: like Dr. Selvig and the SHIELD Agent Hawkeye (Jeremy Renner), who'd been watching out for him while he poked at the god-cube.
- He and his zombots escape with the Tesseract, causing Fury to look cranky and proclaim "as of right now, we are at war" before we're bombarded by a very aggressive title card.