Cassandra both creates and unleashes "X-2"; a virus which ends up killing 99.9% of women on planet Earth. A young boy named Brandon - son to the game's hero Griffon Spade, and Madison, one of the few women who managed to survive the plague - was born with a mysterious power called the "Edge", which both of his parents also hold. Cassandra kidnaps Brandon with intentions of stealing his power for herself. Griffon and Madison fight Cassandra's thugs in California, Texas and Washington D.C., before retreating to her bases in France and Germany.Cassandra takes her final refuge at Alcatraz island, where she climbs into a tank with the capability to turn invisible. She is killed, but the final scene of the ending shows a mysterious man calling her "the chosen one". Through magic, he then brings her back to life.
It would suggest that Cassandra was intended to appear in the third game in the BattleTanx series, however, the project was cancelled before release.