Under the guise of Dr. Dometone, Mumm-Ra lures Lion-O into a battle against four of his most formidable enemies Rataro, Safari Joe, and others in an attempt to eliminate the young ThunderCat.
Mumm-Ra takes Lion-O to a gallery of the ThunderCats accomplishments. However, the pictures can come to life and Lion-O must battle them. Once the other ThunderCats arrive they end up in trouble and Lion-O is confronted by Mumm-Ra who has made himself into a carbon copy of Lion-O. It's Lion-O VS Lion-O and the battle is a draw, until Lion-O shows Mumm-Ra his reflection.