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

Season 2: Episode 47

Chad (from the episode "Double-Edged Sword") comes to Eternos with his older brother, Johno, who is about to be presented with an award for 'boy of the year'. However, Johno is secretly caught up in an obsessive drug addiction- he has been paying Count Marzo for sniffs of The Black Nightmare, a dangerous plant which originated on Trolla. The drug drives Johno to attempt a dangerous stunt during the 'boy of the year' ceremony, which humiliates him and causes King Randor to withdraw his award. However, naive young boys have been impressed by Johno's stunt, and Count Marzo uses the drug-addicted boy to lure them all to his evil services so he can use the flower to get them all under his power... when the heroic warriors realise what is happening, it is down to them to foil Marzo's plan and rescue Johno from his addiction before the children of Eternia are doomed.