In their continuing search for a source of dilithium crystals that could be used to supplement the Voyager's power core, the crew of the Starship come upon a planet that seems replete with the substance. Upon closer examination, they find that the place is really a base for a strange alien culture that must steal bodily organs to fight the "phage," a disease that eats away at their bodies and destroys their organs. Neelix (Ethan Phillips) falls prey to them, and the race is on to save his life.