Jonas is a duplicate. He lives with many other duplicates in a so-called haven, cut off from the world, and has nothing to do but exercise, eat healthily, and take care of his health. However, there is one threat in this seemingly idyllic life: the Frass. A disease that appears suddenly and unnoticed, can affect all organs, and can only be "cured" by the immediate removal of the affected body part. The cruel reality behind this is unknown to any of the duplicates: they are genetic twins of people living in the "normal" world and must always serve as a source of spare parts. One day, Jonas is also afflicted by the Frass.