In the middle of the 21st century, humanity has begun to colonize other worlds. At some point, during their explorations, they come across an alien life form. These so-called Chigs completely wipe out two colonies from Earth, after which the Earth space fleet sent there is completely defeated. Pilots in training and newly graduated cadets are then sent into space. The Wildcards, a group of young astronauts, are followed from the moment they enter service. They are sent out for infantry duties on alien planets and as attack pilots in their SA-43 'Hammerhead' space fighters.