He-Man and the Masters of the Universe (1983)

Season 2: Episode 65

Kobra Khan visits the heroic warriors, offering a truce in exchange for their help. He tells them that his people, the Reptons (a snake clan to whom he belonged before he joined Skeletor's forces) are in need of help- someone has extinguished the furnace which heats their underground kingdom, plunging the whole kingdom into severe coldness. Khan wants them to find the culprit and re-heat the furnace. He-Man, Man-At-Arms, Battle Cat and Orko go to the Reptons kingdom with Khan, but it soon transpires that Khan is not to be trusted... for it was he who extinguished the furnace himself, and he intends to frame He-Man for the crime and expose them, in the hope of gaining the Repton King's crown in return!