One was discovered quite by accident. A man in a mental hospital said he wasn't real. He wasn't.
There were more. Scientists feared that half the population of Earth might be Syns.
Methodically, the Syns were being rooted out and destroyed. In turn, they were carrying on their own fearful destruction of human life and works.
Everyone's humanity had been challenged. Every man was aligned against each other...because no one knew what a Syn was.
REF : 9780575129979