Multiple Nebula Award-finalist Jack McDevitt returns to the world of "Chindi" and "Omega"-and humanity's struggle with its own existence. To boost waning interest in interstellar travel, a mission is sent into deep space to learn the truth about "moonriders," the strange lights supposedly being seen in nearby systems. But the team soon discovers that their odyssey is no mere public-relations ploy, for the moonriders are not a harmless phenomenon. They are very, very dangerous-in a way that no one could possibly have imagined.