NOTE: This spoiler was submitted by Dukes
“The Avengers” opens with Loki (Tom Hiddleston) planning his assault on Earth. He has made a deal with a group of aliens called the Chitauri: they will give him an army to attack Earth, and in return, he will provide them with the Tesseract - a blue cube that provides limitless power - so they can take over the rest of the universe. The Chitauri present Loki with a scepter he can use to obtain the Tesseract.
Cut to Nick Fury (Samuel L. Jackson). He has been called to a secret underground government research facility. The government has been studying the Tesseract, trying to harness its power as an energy source. The Tesseract has been behaving strangely lately, hence why Fury has been called in. Professor Selvig (Stellan Skarsgård) is one of the scientists who has been studying the Tesseract, and a soldier named Barton / Hawkeye (Jeremy Renner) is guarding the cube as well.
As soon as Fury arrives, the Tesseract emits a huge bolt of light and Loki materializes. The government soldiers attack, and Loki knocks them silly with his scepter. He uses the scepter to touch Barton and Selvig on the chest, turning them into zombies who have to obey his command. Barton helps Loki steal the cube and escape, and meanwhile the bolt of light from the Tesseract continues to expand, exploding the underground lab. Fury barely escapes.
Over to Natasha Romanoff / Black Widow (Scarlett Johansson). She is tied up in an old warehouse, tortured and beaten by Russian thugs. The Russians believe they are interrogating her, but in actuality she is subtly extracting information. Mid-interrogation, her phone rings. Fury wants her to leave her current job and go find “the big guy.” Romanoff breaks her bonds, knocks out the Russians, and heads to India.
Bruce Banner / the Hulk (Mark Ruffalo) is working as a doctor in India, whilst hiding from the government. Romanoff lures Banner to a nearby house and convinces him to help locate the Tesseract. Because the Tesseract emits gamma rays and Banner is an expert on gamma radiation, Romanoff thinks he is the best person to track it down. If the Tesseract falls into the wrong hands, it has the energy potential to wipe out the world.
Back to Nick Fury. Fury is talking to the council of his secret government agency, SHIELD. The council wants him to use “Phase 2” to get the Tesseract back. Fury says that Phase 2 is not complete - he wants to use The Avengers Initiative instead.
Fury goes looking for Steve Rogers / Captain America (Chris Evans). Rogers is working out at a boxing gym. Fury tells Rogers about the Tesseract, and explains that the government found it in the ocean when they were looking for Rogers (referencing the events of the “Captain America” movie). Fury enlists Rogers to help with its recovery.
Cut to Tony Stark / Iron Man (Robert Downey Jr.). Stark is soldering a new arc reactor to power the massive Stark Tower he just built in the center of Manhattan. Agent Phil Coulson (Clark Gregg) interrupts Stark’s work to explain the Tesseract problem.
Meanwhile, Loki has taken the Tesseract, Professor Selvig, and Barton to his own secret underground lab. Loki instructs Selvig to use the Tesseract to build some kind of device. Selvig says he will need iridium. While Selvig works, Loki uses his scepter to communicate with the Chitauri. The Chitauri are extremely brutal, and they warn Loki that they will make his life a living hell if he fails in his task.
Back to Agent Coulson, who takes Rogers to a giant military ship where they meet up with Banner and Romanoff. The ship morphs into an air vehicle and takes off out of the water. Banner is extremely uncomfortable being on an airship, considering his “condition.”
Rogers, Banner, Romanoff, and Fury are all attempting to locate Loki. Using satellite facial recognition, they see he is attending a gala in Stuttgart, Germany.
Loki and Barton break into the gala to steal some iridium, which is being held in an underground vault. Barton is still mind-controlled, and he brutally dispatches the guards with his bow and arrows. Once the iridium is in their possession, Loki dons his gold armor and helmet and demands that the crowd of gala attendees kneel before him. Most of the people kneel, terrified by his ability to appear and disappear, but one old man refuses. Loki is about to execute him with his scepter when Steve Rogers intervenes, in full Captain America uniform. Loki blasts Rogers with his scepter, and Tony Stark flies over in his Iron Man suit and blasts Loki right back.
Stark and Rogers subdue Loki and take him back to the airship via a smaller jet (Barton has escaped with the iridium). En route to the airship, Thor (Chris Hemsworth) smashes into the jet and steals Loki. Stark chases after Thor, and Rogers grabs a parachute to follow.
Down on the ground, Thor tells Loki he needs to give up his plan to rule the earth and come home to Asgard. Loki refuses. Stark slams into Thor, and Stark and Thor do battle in the woods until Rogers interrupts them. Rogers convinces Stark and Thor that they need to work together to recover the Tesseract. They grab Loki again and take him back to the airship, where he is contained in a glass cell. The cell has an eject button so that if Loki tries to escape, he can be dropped out of the airship.
In the airship lab, Stark and Banner bond over their super-genius skills. Both Stark and Banner are suspicious of Fury they don’t believe he’s telling them everything about the Tesseract. Stark plans to hack into the airship database, but while he’s working on it, Rogers breaks into a secret storage area to do some snooping of his own.
Meanwhile, Romanoff visits Loki in his cell. She demands to know what he’s done with Barton. Romanoff owes Barton a debt, because back when she was an assassin, Barton was hired to kill her. Instead, he gave her the chance to go straight and work for SHIELD. Loki taunts Romanoff, and it appears that she is breaking down. She cries, “You’re a monster!” and Loki says, “I’m not the one who brought the monster on board.” Instantly, Romanoff’s tears disappear and she says, “So that’s your play. You’re trying to use Banner.”
As Romanoff discovers Loki’s plan, Rogers finds evidence of “Phase 2.” Rogers and the other Avengers confront Fury SHIELD has been trying to use the Tesseract to make super-powered weapons. Fury admits it’s true: when the government was confronted with Thor and the other demi-gods, they realized that humans weren’t alone in the universe and they needed a more powerful way to protect themselves. Thor says that’s stupid - if the humans try to use the Tesseract, they’ll only attract the attention of evildoers across the universe.
While the Avengers are chewing out Fury, Barton is sneaking up on the airship with a group of soldiers. Barton shoots an explosive arrow at the airship, blowing up one of the engines. The Avengers are blasted in every direction. Romanoff is trapped under a pile of rubble, and next to her, Banner starts morphing into the Hulk. He tries to stop the transformation, but he can’t. Romanoff struggles free of the rubble and takes off running. The Hulk chases after her, trying to tear her head off and smashing everything to bits.
The airship is in bad shape, and Stark needs to fix the damaged engine before the other engine fails as well. Stark and Rogers work together to get it started.
Meanwhile, Romanoff is still running from the Hulk. The Hulk corners her and is about to smash her face when Thor comes plowing through. Thor and the Hulk have an epic battle in the hull of the airship. One of the random SHIELD pilots gets in a jet and tries to shoot the Hulk from outside of the airship. The Hulk leaps right out the window and lands on the nose of the jet, tearing it to bits. The jet and the Hulk plummet to the earth.
With the Avengers distracted, Barton and his soldiers infiltrate the command center. Barton uses the computer to shut down the remaining engine, then heads to Loki’s cell. Thor tries to prevent Loki’s escape, but is tricked by Loki’s body double powers and ends up trapped in the cell himself. Romanoff attacks Barton, and Agent Coulson threatens Loki with a Phase 2 weapon prototype. Loki stabs Agent Coulson and hits the button that drops Thor right out of the airship.
Thor plummets to the ground, trapped in the glass cage. Just as the cage is about to hit the ground, he uses his hammer to smash through the glass and leap free.
Back up in the airship, Stark and Rogers get the broken engine working again, and Romanoff hits Barton in the head until he finally shakes off Loki’s mind control. Agent Coulson manages to shoot Loki with the Phase 2 weapon, but Loki escapes anyway. Fury finds Coulson just as he’s about to die. “It’s okay,” Coulson says, “The plan wouldn’t work if they didn’t have something to avenge.”
Fury gives the Avengers a pep talk about how Agent Coulson sacrificed everything because he believed the Avengers could stop Loki and save the world. Fury explains that he never supported the Phase 2 weapon he always wanted SHIELD to rely on the Avengers instead.
Down on the ground, Thor looks around for his hammer and Bruce Banner wakes up naked in a pile of rubble.
Back up on the ship Stark is trying to figure out Loki’s next move. He knows that Loki is dramatic and will want to use the Tesseract in the most stunning way possible. He realizes that the most ostentatious location would be his own Stark Tower.
Cut to Stark Tower where Professor Selvig is setting up his newly created device, powered by the Tesseract. The Tesseract shoots a huge blue bolt into the sky, and a doorway is opened to the outer space location where the Chitauri’s army awaits.
Stark dons his Iron Man suit and flies to Stark Tower. Loki is waiting inside. Stark takes off his suit to approach Loki. He says, “Whether your army comes or not, we’re going to beat you. And if you do manage to destroy the earth, you can be damn sure we’ll avenge it.” Loki hits Stark in the chest with his scepter, planning to use his mind-control trick, but the scepter doesn’t work on Stark because of his mechanical heart. Loki flings Stark out the window instead, and Stark uses a homing bracelet to call his Iron Man suit, so the suit flies out the window and catches him before he hits the ground.
The gateway is open and hundreds of Chitauri warriors fly down on hover boards. They are followed by a giant airship that looks like a flying worm. Stark blasts the hover aliens while Romanoff and Barton back him up in a jet. The giant airship shoots the jet and it crashes.
Thor tries to reason with Loki: he says, “It’s not too late to stop this. We can do it together, brother.” Loki stabs him.
Down on the streets of Manhattan, Rogers, Barton, and Romanoff fight the Chitauri and organize the police force to help evacuate civilians. Just then, Banner rolls up on a motorbike. Stark draws the giant worm ship towards them, and Banner turns into the Hulk and smashes the giant ship to bits. The Avengers form a circle to face off against the remaining Chitauri.
But the gateway is still open, and hundreds more Chitauri fly through, plus three more flying worm ships. Rogers organizes the Avengers to fight the Chitauri, and Thor uses his hammer to call down lightning and electrify the entire Chrysler building to blast one of the airships. Romanoff says, “It’s not enough, they’re just going to keep coming, we have to close the gate!” She has Barton give her a boost so she can jump up and commandeer one of the hover boards to fly to the top of Stark Tower.
Meanwhile, the SHIELD council has decided that the only way to contain the alien invasion is the nuke Manhattan. Fury is freaking out because that will kill millions of civilians, not to mention the Avengers.
Up on the top of Stark Tower, Professor Selvig is hit in the head with a piece of shrapnel, ending Loki’s mind control. Romanoff flies her hover board over to the device and Loki moves to stop her, but the Hulk grabs him and slams him into the ground. Selvig tells Romanoff that he couldn’t stop himself from building the device, but he did manage to create a safety to shut it off: the safety is Loki’s scepter.
Down on the ground, the Avengers are overrun with Chitauri and the nuke is on its way. Fury warns Stark, and Stark knows what he has to do. Romanoff has grabbed Loki’s scepter and she’s about to shut the gateway, but Stark tells her to wait just a minute. He flies over to the nuke and grabs it mid-flight. Using the last of the power in his suit, he flies straight through the gateway with the nuke, and sends it careening toward the massive Chitauri mother ship. Stark’s suit dies, and he slowly falls backward as the nuke explodes the mother ship.
Romanoff sees the nuclear explosion and has to close the gateway. Just as she closes it, Stark falls through and plummets to the earth. Thor tries to grab him, but he’s too far away. Just before Stark hits the ground, the Hulk snags him out of the air. Rogers pulls off Stark’s helmet, but he appears to be dead. Even the arc reactor on his chest is dark. The Hulk yells in fury, and the noise startles Tony Stark awake. He says, “Nobody kissed me, did they?”
The Avengers surround Loki, and Thor takes the Tesseract and Loki back to Asgard to face justice. The SHIELD council is pissed at Fury and they say, “The Avengers are dangerous.” Fury says, “Yes, they are, and now the whole universe knows it.” The final shot is Tony Stark and Pepper Pots (Gwyneth Paltrow) rebuilding the decimated Stark Tower. The letters for “STARK TOWER” have mostly been blown away, so all that remains is a giant “A.”
The credits roll.
After the credits, there is an additional scene:
The defeated Chitauri are mourning the destruction of their empire. A Chitauri soldier kneels before his emperor and says, “The humans are stronger than we thought. To attack them is to court death.” The emperor simply smiles, and we see it is Thanos.
After the credits II:
Their is a 2nd bonus scene at the end of the credits. It's all of the Avengers sitting at a restaurant eating schwarma. No words are spoke. Just them eating and the workers cleaning up behind them.