A next-generation energy source, "NF43", has brought a new age of prosperity to the United Earth (UE). This substance, with its high energy density, can be extremely destructive in the wrong hands, so an international body is established to regulate it. However, crisis mounts when a top UE minister steals a large quantity of NF43, in a false-flag operation that implicates the guardians themselves. As an enraged world mobilizes against the disgraced countries, the culprit defects to 'Red NOIA' (apparently a future communist block). To prevent global war, an experimental robot--the NF43-powered FR-Silver--is deployed to infiltrate the commie HQ and retrieve the stolen material.

Instead of a scrolling shoot-'em-up like previous Fox Ranger games, what we get here is a mecha platformer like Zyclunt or Genocide 2, with a humanoid robotic war machine hacking and slashing its way through a series of stages swarming with hostile machinery. The robot is equipped with some special moves, plus a jetpack, which can extend jumps in mid-air, in a couple of stages it also allows the Ranger to fly, for a short interlude that recalls the series' past. Three skill levels are available.