|The Last Day|
|Original Airdate||September 30, 1988|
|Writer(s)||J. Larry Carroll|
|Previous Episode||The Circus Train|
|Next Episode||Return to Thundera - Part I|
|All Episodes||Episode Guide|
The episode begins with Mumm-Ra at the receiving end of the Ancient Spirits of Evil’s wrath. Exasperated by the mummy’s constant failures and the loss of his allies the Mutants and the Lunataks, the sentient statues grant Mumm-Ra just one day to rid Third Earth of the ThunderCats. To prove their point, they banish Mumm-Ra’s beloved pet Ma-Mutt before transforming Mumm-Ra into his most powerful form yet, destroying his pyramid in the process.
A series of violent earthquakes and volcanic eruptions on every corner of Third Earth mark the beginning of Mumm-Ra’s mayhem. The ThunderCats’ analysis of these geological disturbances predicts a total planetary destruction in less than twelve hours. Suspecting Mumm-Ra to be behind the happenings, the noble heroes set out in search of him in their vehicles.
Tygra and Cheetara are the first two unfortunate souls to encounter the bigger and, according to Tygra, uglier Mumm-Ra. The villain, having attained gigantic proportions and powers, dispatches the two ThunderCats with relative ease, teleporting them to an unknown dimension. Lion-O and Panthro arrive on the scene and put on a brave fight but the latter is transported to join Tygra and Cheetara. In a stunning animation sequence, Mumm-Ra traps Lion-O in a prison of stone and molten lava. The colossal mummy then banishes the ThunderKittens right after he destroys the Tower of Omens with one mighty slash of the Sword of Plun-Darr.
Following Lynx-O’s advice, Snarf arms himself with every item from the Treasure of Thundera and enters the Book of Omens, hoping that the Guardian of the book will divulge the secret to defeating Mumm-Ra. Meanwhile Jaga also joins in the fight and transports himself and the ThunderCats who are trapped in limbo into the Eye of Thundera, giving it enough power to break Lion-O out of his rocky tomb and fly him straight to Mumm-Ra.
Just before Lion-O and Mumm-Ra lock swords again, an image of Snarf appears in the Eye of Thundera and tells Lion-O that he only has to survive until sundown in order to defeat Mumm-Ra. Even though Mumm-Ra clearly has the upper hand in this second round, Lion-O manages to go the distance and as soon as the day ends, the Ancient Spirits of Evil mete out the same punishment to Mumm-Ra as they had to Ma-Mutt. “Is this the end of Mumm-Ra?”, howls the glass-trapped mummy, giving the ThunderCats and the viewers something to ponder over.
- In this episode, the Ancient Spirits of Evil confirm that many years have passed since the ThunderCats first arrived on Third Earth.
- They don't exactly specify how many years have passed, but they mention "year, after year" so one could assume at least 2, 3 or more years have passed since Exodus.
- Despite confirming that many years have passed, WilyKit and WilyKat have not aged while Snarfer has, even though the episode Time Switch implies Thunderians age similarly to humans.