In a comfortable London suburb, the wife of the Commissioner of Police is killed when a parcel bomb intended for her husband explodes in her hands. The latest and most horrific in a series of outrages that has shaken Britain in the late 1960s, the killing alerts Special Branch to the operations of a new and deadly cell of terrorists dedicated to the overthrow of order by the most violent and devious means - the Crystal Faction.

Nick Ryder is one of the undercover team ordered to find and infiltrate the group before it is too late. His adversary is Gabriele Schroeder, founder and leader of a movement more highly organized and ambitious than any other before it. The trail of violence that has led across Europe, from the Paris barricades to a remote Wiltshire farmhouse, reaches a climax of stunning excitement on the London streets.