MAN-MADE HORROR Seven scorching days in August. One-tenth of Sheffield's population suddenly disoriented, hallucinating, catatonic...or dead. Dr. Daniel LIeberman, the town's pediatrician witnessed the first incident when a young girl freaked out at her parents' party--and everyone assumed it was drugs. Especially Paul McGinnis, head of the private lab that was Sheffield's chief industry. But the horrors didn't stop: a psychotic boy brutally murdered a teenage girl; another died when his motorbike smashed into a tree; a librarian became catatonic. And with the speed of a fire storm--an epidemic. But of what? And what would stop it?