There is a phenomenon - a force, a spirit, a flaw in Reality - known as the Essence, which can manifest at random, often with dire effect.

Michael Brookes, an economist working for a small outstation of MI6 attached to the Treasury, is sent to the Netherlands by his department, where he narrowly escapes being kidnapped; and that's just the start of his problems. Michael has never heard of the Essence, but some very powerful people believe otherwise. Despite his protestations, they will stop at nothing to discover what he knows.

The problem is that Michael, who is recovering from a catastrophic breakdown, has large gaps in his memory... So he can't rule out the possibility that they might be right.