Is Earth alone in the universe? In an attempt to answer that centuries-old question, scientists sent probes into the void, hoping they'd be found by intelligent life forms. In hindsight, it's decided that giving possibly hostile races directions back to Earth might be a dangerous idea, and the United Space Force Marines are dispatched to recover the probes. Corporal David Creswell has become a little too close to Blake Bickford, a recent graduate from Marine training, and fraternizing is against regulations. They manage to keep their romance under the radar until they are reassigned to a classified mission to retrieve the probes-aboard a ship where they're clearly not welcome. While trying to discover who is playing with Earth's toys in deep space, they'll give new meaning to "leave no man behind."