Story : The Ro-Bear Berbils are a friendly group of robot bears that live on Third Earth. Lion-O and Snarf don't know this, and end up getting caught in a Ro-Bear trap. The Berbils free them however, and they form an alliance. Mumm-ra attacks the Berbil village, but the Thundercats save it. In return, the Ro-Bears help the Thundercats to build Cats' Lair, a new base for the Thundercats.