Acorna and Aari are taking their daughter, Khorii to meet some relatives at Maganos Moonbase. With them in the spaceship Condor, are their android son Elviiz, Captain Becker, Maak and the Makahomian Temple cats RK and Khiindi. En route, they receive a distress call, a deadly plague is spreading throughout the star system. As Linyaari, both Acorna and Aari are able to heal the sick, they are asked to go to the stricken planet of Paloduro to help the plague victims. They drop Khorii, Elviiz and Khiindi off at the moonbase first. The plague continues to spread and when a supply vessel sends the moonbase a distress call Khorii is determined to go and help, as she is a Linyaari healer too. Khorii, Elviiz, Khiindi and their friends Hap, Asha and Sesseli take a shuttle to the ship. However, by the time they get there only the young daughter of the Captain, Jaya, is left alive. They are forbidden to return to the moonbase in case they have become infected with the plague. They are then contacted by people from a nearby planet asking for help, where Khorii discovers that if she purifies the water it heals anyone in it.Meanwhile, Acorna and Aari have exhausted themselves trying to eradicate the plague, worse they have contracted a strain of the plague themselves and although it cannot make them ill they infect Becker and RK and are too weak to heal them. They send out an urgent distress call and Khorii arrives just in time to save Becker and RK. The plague is contained and Acorna and Aari are put into quarantine, while Khorri and her friends come to the realisation that someone has deliberately created the plague. They set out on a mission to search for the creator of the plague, and to find a way to destroy it.