Vultureman invents a voice imitator which can imitate (anyones) voice. The mutants use the invention to trick the Thundercats into falling for false distress calls. They go on the communication frequency that the Thundercats use and pretend to be Thundercats in danger.
Each Thundercat is lured into a different danger zone of third earth.Wilykit and Wilykat get trapped in the Vortex, Cheetara in a giant bee hive, Tygra in Mole-masters hole, and Panthro gets captured by the mutants. Lion-O and Snarf go off to save them once again, and put the mutant scheme to an end.