Mankind's first alien contact tears into Earth: projectiles launched from Jupiter's moon, Ganymede, have vaporized whole cities. Under siege, humanity gambles on one desperate counter strike. In a spacecraft scavenged from scraps and armed with Vietnam-era weapons, foot soldiers like 18-year-old Jason Wander - orphans that no one will miss - must dare man's first interplanetary voyage and invade Ganymede. They have one chance to attack, one ship to attack with - and their failure is our extinction.