Operation: Matriarchy is a science fiction first-person shooter.

In the 24th century mankind has formed itself into the Federation of Earth, and has colonized several other planets. However, around 2350 a mysterious virus ravages the colony planet of Velia, targeting only the females within the population.

They are transformed into brutal killing-machines, while the males are enslaved for use as sustenance or as subjects for genetic experiments. Having now evolved into an aggressive hive mind, the Velians turn on the Federation, instigating a brutal war.

The game begins seven years into the conflict, when the player character, Senior Sergeant Paul Armstrong of the Federation, finds himself forced to take on the Velians when they attack his ship.