Darius was once a planet that boasted a highly advanced civilization, but fell into ruin after succumbing to the relentless assaults of Belser and his mysterious space aliens.

Proco and Tiat, two survivors of Belser's evil quest, escaped and fled to the planet Orga where they began a new civilization.

Centuries later, the descendants of Proco and Tiat received a strange radio signal emitted from a distant part of their galaxy. To their amazement, it was a May Day signal from another line of Darius descendants who also had survived Belser's terrible assault. Team with the Organites aboard the spacecraft Silver Hawk and blast with them across the galaxy to rescue what remains of the once-proud civilization of Darius.