Neptune's frozen outposts fall silent one by one. Strange signals from the edge of the Solar System draw the carrier ECS Vanguard into the darkness beyond the planets. There, humanity faces a new alien contact—the Blight. These barbaric space Vikings have come to exterminate what they believe is their ancient enemy's latest puppet civilization.

Earth struggles to control the skies with fighters and throws its Lizard shock troops into bloody ground battles. While the war rages, Flex must uncover the truth about the hyperspace rivers connecting the stars, the mysterious Cure that terrorized Venus, and why the Blight believe humanity is already enslaved. The fate of two civilizations hangs in the balance—even as somewhere in the void, a greater horror stirs.

The Neptune War is the third explosive installment in the Pax Solis series, where first contact always turns into a fight to the finish.