The inhabitants of the planet Thundera evacuate just before it is destroyed. They were pursued by a band of mutants. All but one of their escape ships was destroyed. Only a small group of Thunderans (ThunderCats) remained. With only half engine power, the group, which was led by Jaga, had to set a course for the nearest planet. Jaga commanded their ship while the other 7 were in their stasis tubes. Jaga died on their journey to Third Earth and their ship crashed there. Soon they made friends with various groups in the area and they designed a fortress. Mumm-Ra the centuries-old embodiment of evil, along with the mutants that destroyed the rest of the Thunderans are a constant threat. But Lion-O, the new leader of the ThunderCats, with his weapon the "Sword of Omens" will help the Thundercats to have a standing chance.

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The Book of Omens

Episode 4x20; Sep 29, 1989

New Thundera is being torn apart and the Thundercats must present certain artifacts at various dangerous locations that used to be beautiful places, then Lion-O must go into the book and give the Key of Thundera to the guardian of the book ""at the 2

Previous Episodes

Episode NameAirdateTrailer
4x20: The Book of OmensSep 29, 1989
4x19: Well of DoubtSep 28, 1989
4x18: The Zaxx FactorSep 27, 1989
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