A missing astronaut sets her family on a frantic hunt for answers. But the more they uncover, the greater the threat becomes to them — and the world.

After an ambush, Afghan interpreter Ahmed goes to Herculean lengths to save US Army Sergeant John Kinley's life. When Kinley learns that Ahmed and his family were not given safe passage to America as promised, he must repay his debt by returning to the war zone to retrieve them before the Taliban hunts them down.

When Royal Air Force pilot Lt. Kate Sinclair is shot down over Afghanistan, she finds refuge in an abandoned underground bunker where deadly man-made biological weapons - half human, half alien - are awakened.