The Story *snicker* has Odin, Thor and Thor's older brother Baldir (what?) go visit the cave of the Norns, Norse versions of the Three Fates, who explain that Odin must give the Hammer of Invincibility (Asylum couldn't be bothered to look up Mjölnir) to Loki so he can destroy the Tree of Life, as that is what fate has decreed. The worlds must end! Odin is like "No way!" and Thor is all "As if?" and the three storm of the the cave to do battle with Loki.
Loki raises a bunch of giant jackal like CGI monsters to attack Asgard while screaming, "Odin!" over and over again. Odin, Baldir and Thor finally show up and charge into battle where Thor is knocked out almost immediately, Loki tricks Odin into stabbing Baldir, and then stabs Odin himself. Before he dies Odin chucks the Hammer of Invincibility through a magic portal to keep it out of Loki's hands. Thor wakes up and attacks Loki and is only saved an instant death by warrior woman Jarnsaxa. Thor get's all "I must kill Loki!" but after she beats him repeatedly to show him what a useless tit he is they flee Asgard through another portal to Midgard AKA modern day Los Angeles. Jarnsaxa takes Thor on a tour of the alleyways of L.A. where he thwarts a mugging. They stop off at her place (she has a storage room in L.A.) and gives Thor a .45 automatic and an Uzi. He is impressed with this world's weapons.
They retrieve the Hammer of Invincibility by defeating some dude in medieval armor who I guess is the guardian of the Tree of Life. Jarnsaxa wants Thor to go into hiding and to let Loki destroy all the nine worlds, because as long as the Tree of Life is alive they can rebuild. She believes Thor is not yet ready to face Loki and could maybe use a few thousand years practice with the whole fighting thing. And from what we've seen of his skills in this movie you can kind of see her point. But Thor is all "I must kill Loki!" and repeatedly tracks down the god of mischief and get's his ass handed to him each and every time only to be saved repeatedly by Jarnsaxa. Eventually even Jarnsaxa luck runs out and Loki tricks Thor, for about the third or fourth time, and get's a hold of the Hammer of Invincibility. Loki casts Thor and Jarnsaxa into Hell and he proceeds to destroy the Tree of Life.
While in Hell Thor scoops up some molten magma and states, "I'll make my own hammer!" Which he does by sculpting the molten metal with his hands into a real cheezy tinfoil looking prop. Thor climbs out of Hell, lays the beat-down on Loki, and then dashes off to pour some healing potion on the Tree of Life. Thor then revisits the Norns and smashes their loom. The End.
Special Props go to:
The costumer who made all the Asgardians look like Renaissance-Faire hopefuls with out much of a budget. Thor's armor consist of chain-mail that is clearly coming apart at the seams with a half dozen metal plates randomly placed on his chest.
The Hammer of Invincibility is a large lump of stone tied to the end of a stick and looks more like something Fred Flintstone would use at work than a weapon of war.