In the last installment of the Un-United States of Z trilogy, Dr. Zen Marley has endured an epic struggle on his way to Los Angeles. But the city of angels is not the haven that he left just weeks ago. A dangerous faction of desperate survivors has emerged and the rotters are an organized, blood thirsty force against nature.

With Zen's voracious hunger mounting, he and his band of misfits are in a deadly race against time to find what may be a mythical cure. This leads them on a collision course directly into the stronghold of the Pied Piper of rotters, Idriss Kimball. With the country's and possibly the world's fate in his hands, Zen must take a final stand for all of humanity.