She-Ra: Princess of Power (1985)

S1E58 Black Snow

Black Snow blankets Galacia, the homeland of the Selkies, who are convinced Frosta is to blame and are rallying for war against the Snow Kingdom. Determined to prevent the conflict, Frosta and She-Ra venture out to uncover the real cause of the ominous snowfall. Their investigation leads them into the heart of the mystery, where the truth proves far more complicated—and dangerous—than either of them anticipated.