Loki, Brother of Asgardian Thor, god of thunder encounters with a leader called the Other of an alien race known as Chitauri. In exchange for giving the powerful energy source known as the Tesseract to the Other, He promises to give him a Chitari army to conquer earth. On earth, Nich Fury, the director of a company called S.H.I.E.L.D has the Tesseract and his Physicist Dr. Eric Selvig is experimenting on it. Then the energy source suddenly opens a portal that led Loki in. He had a scepter that could be used as a weapon and enslave people. He enslaved most of the agents in the lab including a superhero called Hawkeye, real name is Clint Barton.
*Hawkeye
Nick Fury then gathers all the Avengers. Natasha Romanoff also known as Black Widow is ent to India to get Dr. Bruce Banner, The Hulk, Agent Phil Coulson picks up Tony Stark that's Iron Man. And Fury Gets Steve Rogers, Captain America. Then Loki was captured but freed by his brother Thor and tries to convince Loki to stop and abandon his plan but then he was confronted by Iron man and Captain America. Thor agrees he should be imprisoned. While that was hapening, Banner and Tony was finding the Location of the Tesseract that's been stolen by Loki's Agents. Then Hawkeye and the agents start attacking the Helicarrier that everyones in. So Bruce banner turns into Hulk and goes out of control.
Loki killed agent Coulson which made the Avengers fight Loki. Dr. Bruce Banner fell to the ground from the Helicarrier! Loki goes to Stark Tower which is Iron Man's Building. Then he tries to enslave him but he couldn't because Tony was half robot! So he threw Tony out of the window but then a suitcase falls and when he lyed on it , He got into his iron suit again! Then a whole army of the Chitauri comes from a portal and attacks the city. Then Bruce Banner came and transformed into the Hulk again to save the world. Then Iron man Pushed the army out to space where he couldn't breathe and then he fell down. Hulk saved him. At the end, Thor and Loki teleported the Tesseract to Asgard and the Avengers could be called if needed!