Long time ago, the planet of Darius went into ruin but Proco and Tiat of Darius gave birth to a new planet and named it Orga. After the passing of many centuries, Proco Jr. and Tiat Young receive a strange radio broadcast from the galaxy. They discover the radio broadcast is a mayday signal from another descendant of Darius. They board the Silverhawk, preparing to defeat an evil force and journey to the galaxy.

Description from MobyGames