The Dark Knight of the title refers to both the kick-ass heroine, who risks her life as army Sergeant Knight investigating a devastated colony on Thorus, and Darius, a former colonist and sole survivor of an attack by aliens.

Though forced to assume the appearance of the alien race, Darius retains his personality.  He and Knight are powerfully drawn together in spite of their perceived racial differences as the aliens mass together to overpower the newcomers. 

The writing is taut, forceful and the language is as colourful as you might expect from the equivalent of a marine task force.   I enjoyed Dark Knight, it kept me reading, even though the genre is new to me, and is definitely an adventure packed action story.