It is from a sci-fi novel I read. Fuck me if I cannot remember which one, and my collection is stored away in preparation for moving. But the agents were mindwiped after every mission. One of them was able to keep small slices of repressed memory and slowly came to realize how they were being used and started seeking a way to escape.
Goddamit. Not only did he go back to fox but he stole an idea for his show. This saddens me, especially after how original Firefly was.