From the introduction: A mysterious island has risen from the depths of the Labrador Ocean between the coast of western Greenland and Canada. The investigators are a part of an expedition from the Miskatonic University lead by anthropologist Walter Hartmann to explore the island and to uncover how it has risen from the depths of the ocean. After a short and turbulent introduction in Arkham Massachusetts, the scenario changes setting to a cold and maritime island during the late summer of 1922. Ultima Thule is a short 1-2 session scenario written for 3-5 investigators and pits the investigators against violent prehistoric ape-like humanoids, a traitor in their own midst from a secret society dedicated to their demise, and one of the most dangerous creatures the mythos has to offer, virtually impervious to any conventional weapons.