When Coralie Frazer arrives at Nimbus Station aboard the National Space Research Council starship Triumph, it's not as the engineer she expected to be. Light-years and several wormhole jumps from Earth, she's now the prisoner of her former crew, and they want nothing from her but the blood that keeps them alive. When she's granted a sliver of unexpected freedom, she jumps at the chance to escape—but fleeing seems impossible when Earth might as well be in another universe.

Commander Josiah O'Donnell has his own problems, and taking reluctant command of the newest United States Orbital Guard cutter Bayonet is the least of them. Fresh off medical leave and tasked with locating Triumph and rescuing her crew, he knows the wormholes he's meant to traverse are hazardous—but what's on the other side might be more perilous than he ever imagined.

Desperate to save her fellow captive blood sources, Coralie doesn't intend to fail. Haunted by the memories of his disastrous last assignment, Josiah won't allow more death. There's just one problem: success for either means condemning a thousand others.