It was believed on Earth that the virulent BYDO Empire had been ruined - but now they've returned, as awful as ever. Their vessels and armies are more potent than before, and Earth will certainly be suppressed unless the new R-90 ship can destruct them. Powered with locomotives that launch it into unlike dimensions, and armed with the Round, Shadow and Cyclone Forces, the R-90 has what it takes to thwart all BYDO menaces. The BYDO mothership must be recovered and ruined to wholly wipe out the species from our world.