The collapsing empire
(Book)

"Riding The Flow, an extradimensional field available at certain points in space-time, humanity spreads to inumerable planets through the universe. A new empire arises, the Interdependency, maintaining its control based on the doctrine that no one human outpost can survive without the others. But just as a river changes course, the Flow changes as well. In rare cases, entire worlds have been cut off from the rest of humanity. When it's discovered that the entire Flow is moving, possibly separating all human worlds from one another forever, three individuals--a scientist, a starship captain, and the emperox of the Interdependency--must race against time to discover what can be salvaged from an interstellar empire on the brink of collapse." --,Page 4 of cover.