No matter one's stance on superhero movies, you have to give credit to the great success Marvel Studios achieved with what is referred to as the Marvel Cinematic Universe: Phase One. The six-film series delivered an impressive return on its investment, earning nearly $4 billion worldwide on the $1 billion spent, and that doesn't take into account all the ancillary items and licensing agreements.
The MCU began with the release of Iron Man (2008) starring Robert Downey Jr. as Tony Stark/Iron Man, which did better than expected since the character wasn't well known outside the comics, like Spider-Man and the Hulk. A brief scene after the credits hinted at what was to come with S.H.I.E.L.D Director Nick Fury (Samuel L. Jackson) revealing, “I’m here to talk to you about The Avengers Initiative.” In The Incredible Hulk (2008), Downey had a brief scene and events in Iron Man 2 (2010) were set about the same time. Shellhead's second film seemed just as much about setting up The Avengers with the appearance of Fury, the introduction of Black Widow (Scarlett Johansson), and the discovery of Thor's hammer. In Thor (2011), the Thunder God (Chris Hemsworth) fights his brother Loki (Tom Hiddleston) to protect Asgard. Captain America: The First Avenger (2011) tells the character's origin and brings him into the present day. Throughout the films there are Easter eggs for Marvel Comics readers and fans on the MCU as well as moments that help coalesce these films into one story that concludes in Marvel's The Avengers (2012), which finds Loki working with an alien race known as the Chitauri to conquer Earth.
After Loki steals the mysterious cosmic device known as the Tesseract, which allows him to take mental control of S.H.I.E.L.D agent Hawkeye (Jeremy Renner) and Dr. Erik Selvig (Stellan Skarsgård), Fury and his agents bring together the heroes, but they don't fit well together. They even fight amongst themselves, which was always a fun occurrence in the comics. As the magnitude of the danger increases, Fury is eventually able to focus them on the mission, requiring a bit of subterfuge on his part, which was a good character moment as it made him more intriguing a figure. In New York City, Loki, through the use the Tesseract and a device built by Selvig, opens a portal for the Chitauri. While the battle the invading forces and the Avengers progresses, a mysterious guild decides the best way to handle things is to nuke the city.