Black Widow [bleeding and tired]: Captain, none of this is going to mean a damn thing if we don't close that portal.
Captain America: Our biggest guns couldn't touch it.
Black Widow: Well, maybe it's not about guns.
Captain America: If you want to get up there, you're gonna need a ride.
Black Widow [eyeing a passing Chitauri fighter craft]: I got a ride. I could use a boost, though.
Captain America: Are you sure about this?
Black Widow: Yeah. It's gonna be fun.
Using his shield, he catapults the Black Widow up into air. She latches on to the back of a Chitauri flying chariot. She quickly takes out the Chitauri gunner and leaps onto the back of the Chitauri driver, impaling him with blades. Romanoff is managing to guide the chariot using the impaled blade as reigns.
Iron Man pops in to take a couple of Chitauri chariots shooting at her. He directs his toward Rogers to join him in the ground battle. On his way in, he mows down several Chitauri like bowling pins. The duo work as a team with Iron Man directing a blast into Roger's shield, who deflects the blast to take out more Chitauri.
Iron Man rockets up, wiping out more Chitauri clinging onto a building side. Iron Man flies right by Hawkeye, who we see firing his arrows with deadly accuracy. The Hulk is now on the back of the Leviathan fighting off several Chitauri warriors. Thor joins him as the decimate the wave of Chitauri.
The Hulk rips up a large plate of armors and impales into the back of the Leviathan. Thor turns and uses his hammer to drive the armor plate all the way in, the fatal blow for the large alien beast. It comes crashing through a building and grinds to a halt, lifeless.
The Hulk and Thor step down, admiring their handy work. The Hulk celebrates with a victory punch served on Thor, knocking him out of frame. The green beast musters a gloating snort. On the Stark Tower rooftop, Selvig finally comes to and is no longer under Loki's mind control. On the streets, Army soldiers have arrived and take up the battle with the Chitauri.
Barton reports to Rogers that some civilians have been cornered in a bank. Chitauri warriors have them surrounded. One of them activates a Chitauri hand grenade with a timer, intending to drop it into the huddle of civilians. But Captain America swoops in through a window and takes the alien out with his shield.
He fights off several other warriors, ordering the civilians to clear out. The timer on the grenade gives off an escalating tone that its about to blow. Rogers jumps out the window, using his shield to deflect the blast. Now in a Chitauri warrior's hand, it explodes, killing the rest of the Chitauri in the bank.
But Rogers is still caught in the blast wave, sending him crashing into a car. He's badly shaken, even a super soldier has his limits. Fury's meeting with the Council is not going well.
Fury attends a conference with the World Security Council. The Council has decided to nuke Manhattan on the justification of containment. . . .
Councilman: Director Fury, the council has made a decision.
Fury: I recognize the council has made a decision, but given that it's a stupid-ass decision, I've elected to ignore it.
Councilman: It's a nuclear missile to take out the portal!
Fury: Situated at the island of MANHATTAN!
Fury refuses to comply with their order and shuts off the communication feed.
Meanwhile, Romanoff continues her joyride with her captive Chitauri driver. From behind, she sees Loki closing in on her. He fires at her from his Chitauri chariot. Romanoff leads Loki within Hawkeye's firing range. Hawkeye locks onto his target and lets loose an arrow, but Loki catches it with his bare hand. He turns and gloats.
However, it is a grenade arrow, it explodes - destroying his Chitauri chariot and blasting him onto the Stark Tower. At the same time, Romanoff leaps from her Chitauri chariot onto the tower's rooftop. The Hulk leaps up to the penthouse and confronts Loki. He's about to charge Loki and then pauses when Loki shouts . . .
Loki: Enough! You are, all of you are beneath me! I am a god, you dull creature, and I will not be bullied by...
Hulk flattens Loki with repeated smashes into the floor.
The Hulk: Puny god.
We cut to Selving and Romanoff on the Stark Tower rooftop. Dr. Selvig, now free of Loki's control, reveals that Loki's scepter can be used to close the portal. They see the scepter abandoned, just a few levels below them. Iron Man is blasting away at a Leviathan, but it's armor cannot be penetrated.
Stark: Jarvis, you ever hear the tale of Jonah?
Jarvis: I wouldn't consider him a role model.
Iron Man flies into the mouth of the Leviathan. We see the large beast erupting with explosions from inside. Iron Man burst out of the destroyed Leviathan and crashes down into the street. The Avengers have mounted a counter-attack on an epic scale, but the endless wave of invading Chitauri is relentless.
One by one, we see each Avenger being overwhelmed by the Chitauri: Iron Man is immediately blasted back by Chitauri warriors, knocking him flat. Hawkeye is down to one arrow, he programs it to work as a grappling hook. Hawkeye leaps from the exploding building and shoots the arrow into the building side, allowing him to swing into an office nearby. Hawkeye crashes through the window, now lying on his back in great pain.
The Hulk is fighting off one warrior after another, but a squadron of Chitauri chariots appear and bombard him with a deluge of firepower.
Meanwhile, the council overrides Fury and scrambles a jet equipped with a nuclear missile intended to end the invasion in Manhattan. Fury races out and fires a bazooka at the jet, a direct hit. The jet crashes and burns on the helicarrier's runway.
However, the council had actually deployed two jets. With no more artillery for the bazooka, Fury fires away with his pistol, but it's futile, the jet takes off. Fury radio's Stark to warn him a nuclear missile will arrive in Manhattan in ten minutes. Iron Man is surrounded by Chitauri warriors, who are serving him a relentless beatdown.
Stark uses his thrusters jet out of the there, heading off into the sky to intercept the missile. The jet pilot fires off the nuclear missile, it now rockets toward the city. We cut to Thor and Captain America fighting off Chitauri warriors on the ground.
Roger is blasted in the stomach, knocking him down. Thor wipes out the remaining warriors around them. On the Stark Tower rooftop, Romanoff has retrieved the scepter and prepares to insert it into the Tesseract mounted device. The scepter penetrates the spherical barrier.
Black Widow: I can close it. Can anybody copy? I can shut the portal down.
Captain America: Do it!
Iron Man: No wait!
Captain America: Stark, these things are still coming!
Iron Man: I got a nuke coming in. It's going to blow in less than a minute, and I know just where to put it.
Iron Man captures the missile.
Captain America: Stark, you know that's a one way trip?
Iron Man: Save the rest for the turn, J.
Jarvis: Sir, shall I try Ms. Potts?
Iron Man: Might as well.
Pepper is in a jet, glued to the news broadcast, extremely worried. She doesn't notice her cell phone is signalling.
In the helicarrier, everyone is frozen with silence, watching intently for the outcome. Iron Man guides the missile towards the portal beam. He forces a sharp turn upwards that barely clears the Stark Tower. Each Avenger on the ground look up, following Iron Man's flight path. Iron Man jets through the portal with the missile to the sound of cheers and applause at the helicarrier bridge.
He finally lets loose the missile once it is close enough to the Chitauri base. He collapses back, falling toward the portal just as the massive Chitauri bases erupts in a huge ball of nuclear explosion, also destroying invading Chitauri heading for the portal. The Chitauri warriors on the ground immediately collapse along with the Leviathan, due to the loss of an apparent link control. Iron Man watches, then closes his eyes, and continues falling towards the portal.
Seeing that Stark has not returned after the explosion, Rogers finally gives the order to close the portal. Romanoff shoves the scepter into the Tesseract, the beam extinguishes, and the portal rapidly collapses. However, Iron Man falls back to Earth a split second before the portal disappears.
The Avengers on the ground are amazed and relieved, but they realize he's not slowing down. Thor revs up his hammer to take off to intercept his fall, but the Hulk leaps in and catches the metal man. They come crashing down into the street, the Hulk uses his own body to cushion the impact to protect Iron Man.
The metal suit is motionless, Thor rips off Tony's face cover. They look down to him, Tony shows no sign of life. However the dazed Stark is awakened by the Hulk's roar.
Stark [regaining consciousness]: What just happened? Please tell me nobody kissed me.
Rogers: We won.
Stark: Alright. Hey. Alright. Good job, guys. Let's just not come in tomorrow. Let's just take a day. Have you ever tried shawarma? There's a shawarma joint about two blocks from here. I don't know what it is, but I wanna try it.
They head to the penthouse to apprehend Loki, who awakens to find the Avengers staring down at him.
Loki: If it's all the same to you, I'll have that drink now.
A series of news broadcasts are shown, both praising and criticizing the Avengers. Some time later, Thor escorts Loki and the Tesseract back to Asgard.
World Security Council: Where are the Avengers?
Fury: I'm not currently tracking their whereabouts. I'd say they've earned a leave of absence.
World Security Council: And the Tesseract?
Fury: The Tesseract is where it belongs: out of our reach.
World Security Council: That's not your call.
Fury: I didn't make it. I just didn't argue with the god that did.
World Security Council: So you let him take it and the war criminal, Loki, who should be answering for his crimes?
Fury: Oh, I think he will be.
World Security Council: I don't think you understand what you've started. Letting the Avengers loose on this world. They're dangerous.
Fury: They surely are. And the whole world knows it. Every world knows it.
World Security Council: Was that the point of all this? A statement?
Fury: A promise.
Hill: Sir, how does it work now? They've gone their separate ways, some pretty extremely far. We get into a situation like this again, what happens then?
Fury: They'll come back.
Hill: You really sure about that?
Fury: I am.
Fury: Because we'll need them to.
In a mid-credits scene, the Chitauri leader, the Other, addresses his master . . .
The Other: Humans... They are not the cowering wretches we were promised. They stand. They are unruly, and therefore cannot be ruled. To challenge them is to court death.
His master turns, revealing himself to be Thanos. After further credits, the Avengers are shown eating together in a shawarma joint; the team looks worn out and no one speaks.