The Infiltration into the S.H.I.E.L.D. Crater Investigation Site was an attempt by Thor to take back Mjølnir, which was being analyzed by S.H.I.E.L.D. agents.

Background

Seeking revenge for the infiltration of Frost Giants in Asgard, Thor started a skirmish on Jotunheim.

Odin rescued Thor, Sif, Loki, and the Warriors Three from the Frost Giants and returned to Asgard. At the Bifrost Bridge, Odin ordered the warriors to take an injured Fandral to the Healing Room.

Odin then proceeded to chastised Thor for his recklessness and could get innocent people kill for attempting to start a war with the Frost Giants. Acknowledging that Thor had proven himself to be unworthy to be king, Odin then took Mjølnir from Thor and removed his powers before using the Bifrost to banish Thor to Earth.

Arriving in a wormhole, Thor was knocked over by a truck driven by Doctor Jane Foster and held Erik Selvig and Darcy Lewis as passengers. Thor awoke and realised that he was on Earth, ordering Heimdall to open the Bifrost to return back to Asgard.

He then asked the three which of the Nine Realms was he on, leading to Lewis to pull out a taser. Disgusted by this, Thor stated that nothing could harm him until she tasered him to unconsciousness.

Taken to a hospital, Thor awoke and realised that the doctors were trying to take his blood, causing him to attack. He was quickly sedated and tied to a hospital bed. Thor eventually escaped and was hit again by Foster in the truck, who apologised and took him to her Wormhole research center.

After spending lunch with the group, Thor overheard two men discussing about a hammer found in the ground which no one could lift. Realising that the hammer was Mjølnir, Thor left to its location, where S.H.I.E.L.D. had established an investigation camp.