The Luna-tacks build their fortress with the help of the brute men. They call it Sky-Tomb, and not only is it powerful, but it can travel through the air. It is a mobile fortress. The Thundercats ask the Berbils to help them build a new structure called the Tower of Omens, that would help them easily locate the position of Sky Tomb, and stop the Luna-tacks as fast as possible. (thetvdb.com)