Godspeed

The Godspeed Drive. It is the faster-than-light spaceship drive that made human colonization of the galaxy possible. But it was not invented by humans - it was found in the wreck of an alien ship that drifted into the Solar System. No one understood everything about how it worked, but it linked a hundred star systems together, and made marginal planets like Erin in the Maveen system habitable.
But one day the Godspeed ships stopped coming. Erin and the Forty Worlds around Maveen were cut off from Interstellar commerce, confined to the slow insystem shuttles that were the only spaceships that were left at Muldoon Port.
Jay Hara grew up on isolated Erin, longing for the legendary days when the Godspeed ships spanned the galaxy, and a young man's dreams could take him to the stars. So when an old, sick spacer named Paddy Enderton showed Jay some very strange devices and told him that he had found a Godspeed base out in the asteroid belt, Jay was eager to believe, despite the doubts of his uncle Duncan and his friend, Dr. Eileen Xavier. But when Jay's farm was raided, his animals killed and his mother beaten, by men searching for Enderton, he became convinced that there was truth in Enderton's ravings.
They won financing from the university, and have chartered a ship to take them out to the asteroid belt, in search of the small moving rock marked as Paddy's Fortune in Enderton's navigation device. But the ship is not what they think it is. And the crew and captain have a very different, and deadly, agenda once they find the Godspeed base.