In the US version, players take control of Zana Keene, a pilot for United Government Space Force, and attempt to stop viking terrorists led by Great Hilagi using a transformable mecha-space fighter named the ERX-75 "Chameleon," developed by Zana's grand father Zerrek Keene. In the European version, players take control of Anna Schwinn, a pilot for United Government Space Force, and attempt to stop powerful alien empire named Zorgon V using a transformable mecha-space fighter named Arrow Flash, developed by Anna's father Herbert Schwinn.