The Avengers

Loki arrives on Earth, steals the Tesseract from S.H.I.E.L.D., and enslaves several minds with the scepter — including Clint Barton (Hawkeye) and Erik Selvig. In response, Fury activates the Avengers Initiative.

The team — Stark, Rogers (thawed from the ice a year earlier), Thor, Banner, Romanoff, Barton — spend most of the film failing to cooperate. Agent Phil Coulson is killed by Loki, and Fury uses his death (and some doctored trading cards) to bond them.

Loki opens a portal over Manhattan and a Chitauri army pours through. The Battle of New York is the founding public event of the superhero age. The World Security Council fires a nuclear missile at Manhattan; Stark carries it through the portal into space, sees the fleet on the other side, and nearly dies. He survives, but the vision of what's out there gives him post-traumatic anxiety and an obsession with pre-emptive defence that drives his behaviour for the next six years.

Post-credits: the first appearance of Thanos.

Standing at the end of Phase One: Six Avengers. Public superheroes. Loki in Asgardian custody. Tesseract on Asgard. Scepter (Mind Stone) confiscated by S.H.I.E.L.D. — and quietly retained by HYDRA agents inside it.

The team spends most of the film failing, and the failure is deliberate: the scepter's Mind Stone amplifies whatever resentment is already in the room, which is why the argument aboard the helicarrier turns as vicious as it does. Loki's plan was never to win the fight on the ground — it was to be captured, get aboard, and let them do the rest.