In the world of the near future, a new powerful drug is becoming widespread - drug "C". Agent Fred, an undercover cop, is tasked with tracking down a small-time supplier of a dangerous substance, drug addict Bob Arctor. But is this true? Or is Agent Fred just a game of Bob's fevered mind? Who is who now, when the boundaries of reality are so unsteady? The novel won the British Science Fiction Association Award in 1979 and was filmed by Richard Linklater in 2006.