This is basically the story of a farmer turning cats loose to wipe out mice that are stealing food.

Except the farmer is an intergalactic empire, the mice are rebels and space pirates, and the cats are randomly chosen humans from present-day Earth.

Margaret was one of the fortunate few to be selected, drafted to fight on an alien planet for overlords she never knew existed. Dropped onto a fantasy world where things like toilets are nonexistent, how does an architect/engineer fight back? By building, of course.