The mystery of the Stone Builders deepens when Constance Young, now captaining the UEF Resolute, stumbles upon a large piece of a space ship made of stone in a solar system not yet explored. An assortment of experts from the original study of Stone Builder artifacts is quickly assembled to investigate. Obviously, this is not the entire ship, and there are no bodies aboard, so they must have had time to escape. Some of the investigators take off in a scout ship to see if they can find any lifeboats, and they do. But it is already claimed by other humans looking to make a name for themselves. And now that the searching ships have landed on this planet, none of their electrical equipment works. Will they ever find a way back to space, back to their friends and loved ones?

As they attempt to escape the planet, another ship appears, bearing down on the research team, but not responding to radio hails. Could it be the stone builders, looking for vengeance for their wrecked ship? Or even worse... the people who wrecked the stone ship?