The Lemmings have found a new playmate: a walrus! The rodents ride it across the entire hut and then slide it onto the roof, before starting over. Grizzy intervenes and manages to eject the animal to the bottom of a mysterious ice cave. In its center, a dolmen on which is a bone. Anyone who touches it is made docile and its appearance becomes prehistoric. The Lemmings hatch a plan in which Grizzy would bend to their will ...