Onboard the International Space Station, Naval Astronaut Claire McFadden is enjoying another routine mission in space when an unexpected explosion cripples the station. With one of her crewmates dead and the station quickly losing altitude, she struggles to bring it under control and buy the crew time until rescue hopefully can come. Unfortunately, NASA does not have a manned spacecraft to reach them, and the other international space agencies cannot or will not help, leaving the crew stranded.

With the station coming dangerously close to a fiery reentry, her old love and fellow former Navy pilot, Steve Paige, offers a radical and risky solution. The company he works for as a test pilot is developing a next-generation spacecraft, the Valkyrie. However, Steve is conflicted about his motive for volunteering for the mission. Is it duty to fellow astronauts or lingering emotions for Claire?

As NASA and the U.S. State Department scramble for a solution, Claire investigates what caused the improbable accident. She learns of a sinister plot to use the ISS as a retaliatory weapon aimed at Washington, D.C. This compels her to try to piece together who and how the station was sabotaged before it is too late.

The people behind the attack will stop at nothing to keep the identity of the culprit a secret. Even if someone can save her and the crew, Claire is the only one who knows what really happened, making her the target of an international assassin. The stakes are high as all parties understand that the incident could spark World War III.