Possessing physical attributes repulsive to "normal" humans, Youn Suu is Expendable -- a dedicated member of the highly skilled and highly disposable Explorer Corps. Embarking on a typically suicidal undertaking with her partner, Tut, Youn has been entrusted with the rescue of a defenseless planet from the Balrog -- a mosslike alien intelligence that is prescient, powerful, and insidious. When the mission goes horribly wrong, only the timely intervention of Expendable legend Admiral Festina Ramos saves Youn and Tut from destruction, as they escape to a seemingly innocuous and deserted world where the true scope of a galactic nightmare will be revealed. Because what came before was only the opening gambit -- and the Balrog's next move may be catastrophic for the Corps and countless imperiled beings.