The Asgardian Loki encounters the Other, the leader of an extraterrestrial race known as the Chitauri. In exchange for retrieving the Tesseract,2 a powerful energy source of unknown potential, the Other promises Loki a Chitauri army with which he can subjugate the Earth.
Nick Fury, director of the espionage agency S.H.I.E.L.D., and his lieutenant Agent Maria Hill arrive at a remote research facility during an evacuation, where physicist Dr. Erik Selvig is leading a research team experimenting on the Tesseract.
Agent Phil Coulson explains that the object has begun radiating an unusual form of energy. The Tesseract suddenly activates and opens a portal, allowing Loki to reach Earth. Loki takes the Tesseract and uses his scepter to enslave Selvig and several agents, including Clint Barton, to aid him in his getaway.