The Tesseract s a powerful Asgardian artifact created by Odin which possesses the abilities to create infinite energy, which can be used to create wormholes to other parts of the universe and different dimensions, rather than reality manipulation. Unknowngly why, the Tesseract was hidden on Earth.
During the World War II it was found by and Red Skull and Hydra as part of their plans of world domination. Hydra's lead scientist Arnim Zola managed to harness the energy of the Tesseract to power weapons to be used against the Allies. Captain America foiled Schmidt's plan to use the Tesseract to launch an aerial attack on the United States in a highly advanced plane by damaging the conduits transferring the Cube's power to the ship. In a desperate attempt to use the Tesseract for himself, Red Skull is apparently desintegrated after the Cube briefly opened a portal to another dimension. Captain America managed to crash Schmidt's plane with the cost of his disappearance in the cold waters, the cube is recovered by Howard Stark while seeking out the fallen Steve Rogers.
Years after being in S.H.I.E.L.D. custody for investigation, the Tesseract started acting strange, it was revealed that Loki re-activated it from another point of the universe in order to transport himself to where it was and steal it. Loki made a deal with an alien race known as the Chitauri, he would give their master the Tesseract in exchange of an army with which he could conquer the Earth.
Loki allowed himself to be defeated by S.H.I.E.L.D.'s newly formed team of superheroes called the Avengers, so he could distract them in order to give his allies the time necessary to build a machine which could concentrate more energy of the Tesseract in order to open a bigger portal to let the Chitauri invade Earth. Loki escaped from the S.H.I.E.L.D. Helicarrier and arrived to Stark Tower, the place with the necessary source of energy to empower the machine in which the Tesseract was used. The Avengers managed to defeat Loki and his invading forces, nuking almost the whole Chitauri army before closing the portal, when the machine was deactivated.
In the aftermath, Avengers member Thor used the Tesseract to return it, himself and Loki back to where they belonged, Asgard.
|Media||Thor | Thor: The Dark World|
|Characters||Thor | Jane Foster | Odin | Sif | Heimdall | Fandral | Volstagg | Hogun | Erik Selvig | Darcy Lewis | Frigga | Phil Coulson | Nick Fury | Clint Barton|
|Enemies||Loki | Destroyer | Laufey | Malekith|
|Miscellaneous||Asgard | Mjolnir | Warriors Three | Bifrost | Earth | S.H.I.E.L.D. | 9 Realms | Casket of Ancient Winters | Yggdrasil | Rainbrow Bridge | Gungnir | Tesseract|