When Seebling Beau Garnie falls through an open portal into the dwarf realm of Calorean, the last thing he expects is to be rescued by super-intelligent rats. A first class hare rider and trained warrior, Beau must drink a solution of Invisimin every day to survive. Unfortunately, someone has raided the Invisimin mines and they are almost empty. Battling dark forces and strange creatures, Beau and close friend Skyle cross Calorean to find the legendary lost mines containing the mineral upon which their lives depend.