There are aliens out there, and we're part of their family tree. It's the dawn of the 26th century and humanity has come into contact with three other alien species. To freighter captain Nick Roan, their existence is just another fact of life, much like Earth's depressed economy and his recent failed romance. But a scientist friend's discovery brings Roan to the center of galactic intrigue. The scientist has been looking into panspermia, a theory that suggests life as we know it was seeded by a passing comet. He wants Roan to help transport him to the comet's supposed origin and possibly prove all four species share the same lineage. Roan thinks the story is bull...until the friend is murdered. From then on, it's a chase through the stars. Pursued by a maniacal alien commander who wants the glory of the discovery for himself, Roan hitches a ride on his ex-lover's freighter and embarks on a quest to answer the age-old question: where did we come from?