While hiding from the unstoppable lizard army, Lion-O encounters a race of creatures who live out their entire lifetime in 24 hours, and learns a valuable lesson about hope.

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.