Thor's Hammer

SG-1 visits the planet Cimmeria (P3X-974), a planet inhabited by Viking descendants, in search of allies against the Goa'uld. Upon arrival, O'Neill and Teal'c are trapped in a labyrinth, where the only exit is through Thor's Hammer, a device to destroy Goa'uld, but preserve the host. Goa'uld weapons are rendered inoperative but not earth guns.