Sergeant Julie Porter didn’t ask to be reinstated, nor did she ask to be reunited with her old squad—a specialized unit inside of the already specialized Delta force. But the army needs Julie’s unique skills for a unique mission, and, unfortunately for her, they aren’t giving her a choice.

The job: rescue the civilian staff of a submarine base located two miles beneath the Atlantic ocean.

It wasn’t meant to be a combat mission, but Julie and her team are ambushed the moment they arrive. Outnumbered and outgunned, they retreat into the Azores Fracture Zone, a network of endless caves that descends to the very core of the earth. Cornered, with no hope of escape, Julie battles a Terran race never before encountered by mankind.

Three billion miles from home, Commander Xianx Paul helms an antiquated space station orbiting Tangent, a lonely planet at the edge of the solar system. Tangent is a fabled El Dorado, its wealth taking the form of artifacts left behind by its long-lost civilization—powerful relics that have attracted some of the system’s most dangerous criminals.

Understaffed and underequipped, Paul’s crew struggles to maintain order with nothing but the distant threat of military retaliation to back them up. But when an admiral arrives from Central Command intent on advancing her own career, she dismisses Paul’s warnings, accuses him of inaction, and wages a reckless war against a savage gang of smugglers.

But there are more eyes on Tangent than anyone realizes. As other forces rush in to take advantage of the turmoil, Paul and his crew are trapped in a desperate, three-way battle for their very lives.