In the year 2050, the solar system is invaded by aliens called the Invid. The human race is attacked by the aliens, but only Earth is occupied, defeated by overwhelming power and numbers. The aliens are always in their mecha and never reveal their true nature. The only free humans are in bases on Mars and the moons of Jupiter. They launched a recapture mission soon after, which was promptly slaughtered by the Invid. It almost seems as if the aliens can sense the energy used by the human forces In 2080, the children of the soldiers that went to Earth are the next generation of Mars Base troops and are armed with their own transformable mecha. This assault is only slightly more successful then the one thirty years ago. Three years later Mars Base launches the Second Earth Recapture Force, consisting of hundreds of ships and mecha. Among them is the 21st Armored Division, commanded by Lt Cmd Stig Bernard. Though they fought valiantly, the Mars Base troops are defeated with heavy losses. During the battle, Scott`s fiancee Marlene is killed and his Legios crash lands in South America. Turning his sorrow and anguish over Marlene`s death into revenge, Stig begins his long trek north to destroy Reflex Point, the Invid`s main hive. Along the way, Stig encounters several charismatic individuals who have been waging their own one-man wars against the Invid. Ray, a cocky, idealistic wanderer; Yellow, a former Mars Base pilot, disguising himself as a female pop singer; Houquet, a tough, lone wolf; Jim, a mecha mechanic who hates war; Marlene, who is actually a stage five Invid that looks like Stig`s dead fiancee; and Mint, a young girl who always causes trouble for the group. The group`s members become more than soldiers, they become close friends, almost a family.

*** Description taken from animenfo.com