The Captain of the renegade destroyer, the U.S.S. Watch, is not really the Captain of his ship. Based on a job-sharing philosophy, the crew of the ship exchange jobs with each other whenever the bell rings. But they can never go to an American port, because if they do, the ship will be decommissioned and the sailors would be reassigned--or thrown into the brig. However, recent astronomical discoveries have led the Pentagon into summoning the Captain to their offices to be re-assigned anyway--to a manned post on the Hubbell telescope. What is "out there" that could terrify the government?