Earth is attacked by the Kulkus, a hostile alien breed infected by a lethal virus and needing human blood to develop an antidote. The worldwide governments negotiate with the humanoid ambassador the terms of peace, giving eight million humans shared between the nations to the aliens and in return they would spare our planet. When Heather Chase, the daughter of the scientist Stephen Chase, is one of the selected, her father fights to save her, joining the resistance force. He proposes to Blair and Alex, the leaders of the resistance, to give his researches with some alien material found in 1947, exchanging for the liberty of his daughter. But Heather is an unique species, having a genetic that heals the aliens and they do not accept to release her.