Nation of Sheep

Cathy Trenton, the O'Malley's adopted daughter, escapes death in a series of events that leads her to the cave of a monk. She figures out that she is somewhere in the mountains where the headwaters of the Darling River start. The monk nurses her to relative health. However, the demons of a mad man chase her. In an effort to help the monk keep his own sheep alive she seeks out the other ranchers in the area whose sheep are also dying. This only worsens her plight.
The sheep scheme finally comes home to roost with Cathy in it's web. But she finds little time for that nonsense for she has her own problems. Part of her dilemma is Ray Cronin. Next is her obligation to the Lama. Then of course, there is Ricky Mann and the predicament with the missing serum. She cannot decide how she can put aside the jealousy found in her relationship with Ray. Yet, she doesn't want to lose the one thing she cannot survive without, especially in the Outback. She rationalizes and contemplates these dilemmas until she decides that a mission in saving the sheep, rather than having to own up to her emotions, is the only way to save her sanity.
The monk and Cathy find a unique way to tend to the sheep and a way to travel among the sheep ranchers. However, the sheep keep dying and no one including Cathy can figure out why. A witch and a mad man shift the balance of power and it swings from him then back and forth between he and the witch. Lisa Mann's son Ricky becomes the pawn, put he is in the situation in the first place because he lost the antiviral, which Dr. Man sent him to Australia to test.
Lisa Mann, head of a special hospital across from New Scotland Yard finds out that the virus she is working on has unexpectedly fallen into the hands of the wrong people. Why her son gave the virus to them she does not know but aims to find out. In the process, she learns that a witch is involved in the scheme and becomes very anxious about Cathy and her son Ricky.