Many worlds within the Robotech Universe besides Earth have felt the ravages of the alien Invid. On Praxis, the Invid have conquered the entire female Amazon population, and are using the planet itself for mysterious experiments.One small group of captives has managed to escape, but they have found themselves trapped in a large cavern beneath the surface, filled with strange prehistoric plants and animals. While the women navigate the unknown dangers of this strange underworld, the planet seems to be destroying itself with a series of increasingly violent quakes. The tremors are the result of the Invid’s experiments, and the female refugees soon discover that the aliens have already abandoned the planet, taking their captives with them. This small group of warriors struggles to get off the planet themselves before it self-destructs, vowing revenge for the deaths of their many sisters and the loss of their homeworld.