A prophecy is fulfilled when Peter Attis is rescued from the Cylons in order to save humanity with the plague of the tongue. Or so it seems...
While harvesting algae for conversion into food, the beleaguered human/refugee fleet is discovered by a small group of Cylon raiders. A brief battle ends with the destruction of a Cylon heavy raider. A colonial issue escape pod found floating among the debris reveals two survivors inside: Singer Peter Attis . . . and his captor, a Cylon Number Eight.
Soon after Peter's liberation, people begin babbling incoherently and dropping into comas. Unwittingly, Peter has been spreading a highly contagious, nerve-deteriorating Cylon biological weapon -- and he just performed for half the fleet. As Dr. Gaius Baltar begins work on a cure, word starts to spread that a fanatical sect believes that Peter is the religious leader who will save humanity and that this virus is their path to salvation. They are willing to do anything to keep Baltar's vaccine from being distributed.
While the fleet is in chaos, a larger Cylon force appears. A weakened humankind, now threatened on two fronts, may be unable to defend itself...