 The Avengers rally in defense of New York City , the wormhole 's location , but quickly realize they will be overwhelmed as wave after wave of Chitauri descend upon Earth . Banner arrives and transforms into the Hulk , and together he , Rogers , Stark , Thor , Barton , and Romanoff 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 of Loki 's control , reveals that Loki 's scepter can be used to shut down the generator . Meanwhile , Fury 's superiors 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 to 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 . 
