<P> In Stuttgart, Barton steals iridium needed to stabilize the Tesseract's power while Loki causes a distraction, leading to a brief confrontation with Rogers, Stark, and Romanoff that ends with Loki's surrender . While Loki is being escorted to S.H.I.E.L.D., Thor, his adoptive brother, arrives and frees him, hoping to convince him to abandon his plan and return to Asgard . After a confrontation with Stark and Rogers, Thor agrees to take Loki to S.H.I.E.L.D.'s flying aircraft carrier, the Helicarrier . Upon arrival, Loki is imprisoned while Banner and Stark attempt to locate the Tesseract . </P> <P> The Avengers become divided, both over how to approach Loki and the revelation that S.H.I.E.L.D. plans to harness the Tesseract to develop weapons as a deterrent against hostile extraterrestrials . As the group argues, Barton and Loki's other possessed agents attack the Helicarrier, disabling one of its engines in flight and causing Banner to transform into the Hulk . Stark and Rogers work to restart the damaged engine, and Thor attempts to stop the Hulk's rampage . Romanoff reluctantly fights Barton, and knocks him unconscious, breaking Loki's mind control . Loki escapes after killing Coulson and ejecting Thor from the airship, while the Hulk falls to the ground after attacking a S.H.I.E.L.D. fighter jet . Fury uses Coulson's death to motivate the Avengers into working as a team . Stark and Rogers realize that for Loki, simply defeating them will not be enough; he needs to overpower them publicly to validate himself as ruler of Earth . Loki uses the Tesseract, in conjunction with a device Selvig built, to open a wormhole above Stark Tower to the Chitauri fleet in space, launching his invasion . </P> <P> Rogers, Stark, Romanoff, Barton, and Thor rally in defense of New York City, the wormhole's location . Banner arrives and transforms into the Hulk, and together the Avengers battle the Chitauri while evacuating civilians . The Hulk finds Loki and beats him into submission . Romanoff makes her way to the wormhole generator, where Selvig, freed from Loki's mind control, reveals that Loki's scepter can be used to shut down the generator . Meanwhile, Fury's superiors from the World Security Council attempt to end the invasion by launching a nuclear missile at Midtown Manhattan . Stark intercepts the missile and takes it through the wormhole toward the Chitauri fleet . The missile detonates, destroying the Chitauri mothership and disabling their forces on Earth . Stark's suit runs out of power, and he falls back through the wormhole just as Romanoff closes it . Stark goes into freefall, but the Hulk saves him from crashing into the ground . In the aftermath, Thor returns Loki and the Tesseract to Asgard, while Fury expresses confidence that the Avengers will return if and when they are needed . </P> <P> In a mid-credits scene, the Other confers with his master about the failed attack on Earth . In a post-credits scene, the Avengers eat in silence at a shawarma restaurant . </P>

Who do the avengers fight in the first movie