The war against the Elai has moved into the enemies' home system after several years of brutal and bitter fighting across known space. Even though their fleets are bottled up and their planets are under a tight blockade by the humans, the United Earth Alliance's technological edge is slipping as the Elia deploy new and more desperate weapons. A strategic strike to cut the Elai off from their fuel supplies goes disastrously wrong, leaving the UEA Marines and the Valkyries cut off and fighting for their lives on an airless moon. They will soon find out that cornered enemies are often the most dangerous.