Psychologist Reed Chalmers speculates that the mental problems of his patients may stem from their minds not being fully in tune with the world they live in, but rather, partially in sync with other, parallel universes.

Chalmers has devised a system of symbolic logic to encode the underlying assumptions of a universe into a mathematical formula, the use of which he believes could affect such a realignment.

Dissatisfied with his life, he attempts to use his boss's process to project himself into the world of Irish heroic mythology, where with his modern knowledge he thinks to set himself up as a wonder worker.

However, interdimensional travel proves an inexact science, and he misses his target reality landing instead in the decidedly colder, bleaker world of Norse myth.

Moreover, the adjustment is complete; now speaking Old Norse, Shea is unable to read the English language Boy Scout Handbook he has brought as a survival manual—worse, he finds his new world's superstitious, pre-scientific belief system encoded in its basic physics.

There the Gods engage in contests with their hosts: Thor incredibly loses a wrestling match with an ancient crone, while Loki is beaten in an eating competition.

Realizing that the weapon they seek may be present under similar disguise, he finds Thor's hammer bespelled beneath the appearance of a quiver of arrows.

The two find prison life brutal and dull, passing the time by racing cockroaches until Shea comes up with a scheme to trick their troll jailer Snögg into releasing them.