Years ago, Jason and Eve — along with their battle tank Sofia MA-01 — defeated the Plutonium Boss and saved the Earth from being consumed from within. Life continued: they married, had two children — Roddy trained in Sofia combat, Elfie in engineering — and kept defending the planet from threats as they arose. But Jason and Eve are dead now. Roddy must take his father's place, and an old threat appears to be stirring again.