The ThunderCats continue their quest for the Book of Omens, which leads them to the fabled Tower of Omens. However, they will first have to get past a series of deadly traps in order to reach it. Meanwhile, Mumm-Ra grows tired of waiting and forces Jaga to reveal the Book's location, and plans to go there himself to take it at all costs.

While traveling, Lion-O's cockiness loses him the Sword of Omens to the Duelist, a villainous sword-collector. With the help of the listless Drifter, Lion-O must get it back.