He-Man and the Masters of the Universe - Season 2 Episode 1 The Shadow of Skeletor

When Beast Man crashlands by Palace Eternia in one of Skeletor's shuttles, Adam, Teela, Man-At-Arms, Man-E-Faces and Ram Man discover that he was being sent to the Dark Moon of Eternia. Curious as to why Skeletor wanted to send him there, they imprison Beast Man in jail and take the ship up there themselves. Reaching Eternia's Bright Moon, they discover that Eternia's two moons are at war with one another after a resident of the Dark Moon reported seeing the people of the Bright Moon causing severe destruction on the Dark Moon. Knowing that the residents of the Bright Moon are innocent, the heroic warriors realise that Skeletor must be the real cause of the destruction, and so Man-E-Faces disguises himself with a Beast Man costume, and goes to the Dark Moon to spy on Skeletor and his warriors and foil their scheme.