Five years have passed since the events of "Indiana Jones and the Kingdom of the Crystal Skull". Indiana Jones has received word that another artifact has been discovered: the hammer of the Norse god Thor. Jones goes to his helicopter to find the legendary hammer. He meets a man in Scandinavia who lives in the mountains where the hammer was reported to be located. Together with a group of Scandinavian archaeologists, they travel to the highest mountaintops of Scandinavia and enter a hidden cavern.
Inside, statues of Viking warriors come to life and attack the group, with only a few of them surviving the battle. Eventually, they reach the chamber where the hammer is held. Jones approaches the pedestal on which the hammer rests, grabs the hammer, and feels a sudden surge go straight through him.
Just then, large dragons erupt from the floor, and the archaeologists escape as Jones battles the dragons with the hammer. He eventually defeats the dragons and escapes as the cavern collapses. The archaeologists are happy to have made it out with both their lives and with the hammer, which they can proudly display to the world.