 After stopping Beastman and Evil-Lyn from breaking into Castle Greyskull, He-Man, Teela and Man-At-Arms learns that it was a test and Prince Adam, Man-At-Arms, Teela, Orco and Cringer are sent on a secret mission to Zagraz Mountain where Zagraz, a elderly wizard reveals he once tried to use his powers to control two comets, but his Zagraz lost confidence in himself when his powers caused him to destroy one of the comets leaving the comet evil. Skeletor takes control of the Cosmic Comet and set out to destroy He-Man and Castle Greyskull once and for all. Can He-Man help Zagraz regain his confidence and stop Skeletor from using the cosmic comet from destroying Castle Greyskull?