Alpha Fleet — B.V. Larson

The Imperials have devised a cunning new method of destroying Rebel worlds. Captain Leo Blake is largely responsible for both our survival and our current predicament. He and his crew are infamous among the stars. As a result, when ships of an unknown configuration begin flowing out of swirling rifts above Earth, Blake is called upon again to deal with the problem.

But the approaching fleet isn't what it seems. They're employing an entirely new way to exterminate Rebels. They will accept nothing less than conquering Earth - or, better yet, destroying all life on our planet.