Lion-O and Pumyra split up with the rest of the ThunderCats in order to get the Sword of Plun-Darr away from Mumm-Ra and his forces. As they continue to flee, the story behind the birth of the Sword of Omens and the Sword of Plun-Darr is told.
With Mumm-Ra arriving at Mount Plun-Darr, Lion-O decides to split the group up in order to take the fight away from the freed cat slaves: he and Pumyra flee into the mines with the Sword of Plun-Darr, while the remaining ThunderCats standby at the Thundertank. But as Lion-O and Pumyra dash into the mines, Mumm-Ra is able to use his dark connection with the Sword of Plun-Darr to track their every move.
A flashback begins that details how the Sword of Plun-Darr and Sword of Omens came to be. The Sword of Plun-Darr was created after Mumm-Ra was instructed by the ancient spirits of evil to destroy the “Star of Plun-Darr” in order to harvest a rare ore with miraculous power. Leo (Lion-O’s ancestor) begins to rethink his position after watching Mumm-Ra destroy the star and kill billions of lives in order to forge a powerful sword out of the ore. Unknown to Mumm-Ra, Leo decides to go against him by using the remaining shards of the ore to make a powerful weapon to aid his planned rebellion: the Sword of Omens.
Back in the present, Lion-O has Pumyra hold the Sword of Plun-Darr and separates from her in order to take out more of Mumm-Ra’s warriors. This soon proves to be a poor decision, as Pumyra is easily caught by Mumm-Ra and loses the sword in the process. Caught in a choice between rescuing Pumyra or recovering the sword, Lion-O decides to save Pumyra and escapes from the underground mine.
The flashback in this episode is meant to show how Leo, Lion-O’s ancestor, decided to rebel against Mumm-Ra in order to save the lives of many different species. The actual episode showing the full rebellion was way back in the 7th episode, Legacy, where Lion-O found himself inside the Book of Omens and had to live out Leo’s final battle against Mumm-Ra. Anything related to that time has been the meatiest parts of the series for me, as they really flesh out the background of this entire world of ThunderCats. If this series had not been cancelled, would we have eventually seen Lion-O and the ThunderCats progress into a battle against Mumm-Ra somewhere in space? I’m very unfamiliar with the elements of the classic ThunderCats series, so these aspects are very new to me.
What I respected more about this episode compared to Legacy was how we see Leo’s personality more fully here than we did when Lion-O was inside his body. There is a much better understanding now that aside from their sense of loyalty, Leo and Lion-O really aren’t all that different when it comes to protecting lives. It would have been great to see how Mumm-Ra encountered Leo and why he began trust him so much to the point of saying “I’ll let you rule a planet one day”.
Going on to the present events, I was a bit confused when Mumm-Ra used his magic in order to make a tracking device on the Sword of Plun-Darr. Why didn’t he just do that before in order to deduce that his sword was at”Mount Plun-Darr? The only plausible ideas that come to my mind is that he has been so focused on getting the Sword of Omens that he never considered it, or his magic has a range limit. Either way, he has the sword now and finally wields the most menacing power in the series so far. My only complaint in regards to Mumm-Ra getting the sword was how quickly Pumyra was captured and tied up. Seriously, Lion-O literally runs around a corner for about five seconds, runs back after hearing Pumyra scream, and finds her all tied up on the other side of the large cavern.