Another thrilling adventure for the ThunderCats, when they stage a daring rescue attempt that tests them to their ultimate limits. After the destruction of Thundera, Mumm-Ra discovers that three Thunderians have survived and are living in peace with their rescuers, the Berbils. Mumm-Ra enlists Hammerhanc and his wicked crew to capture them, and uses his new captives to lure the ThunderCats to the one place that will rob them of their powers - Fire Rock Mountain. Determined to save their fellow countrymen, the ThunderCats rise to the challenge - but is the challenge too great?...
| Actor | Role |
|---|---|
 Bob McFaddenLynx-O / Snarf / Slythe / Grune the Destroyer / Ratar-O / Captain Shiner / Topspinner (voice) (as Robert McFadden) | Lynx-O / Snarf / Slythe / Grune the Destroyer / Ratar-O / Captain Shiner / Topspinner (voice) (as Robert McFadden) |
 Earl HammondJaga / Mumm-Ra / Vultureman / Snowman / Turmagar / RoBear Bob / Nisida / Hammerhand (voice) | Jaga / Mumm-Ra / Vultureman / Snowman / Turmagar / RoBear Bob / Nisida / Hammerhand (voice) |
 Larry KenneyLion-O / Jackalman (voice) | Lion-O / Jackalman (voice) |
 Lynne LiptonCheetara / Wilykit (voice) | Cheetara / Wilykit (voice) |
 Earle HymanPanthro / Pilot / Guard / Cruncher (voice) | Panthro / Pilot / Guard / Cruncher (voice) |
| PPeter NewmanTygra / Wilykat / Bengali / Monkian / Hachiman / Rambam (voice) | Tygra / Wilykat / Bengali / Monkian / Hachiman / Rambam (voice) |
| GGerrianne RaphaelPumyra (voice) | Pumyra (voice) |