Detective Superintendent Roy Grace is investigating the bizarre slaying of Katie Bishop, a member of Brighton's social elite. Her husband Brian appears to be in the clear - he was in another town at the time, sound asleep. But Grace begins to suspect the presence of a doppelganger: is someone else - almost identical to Bishop - involved in the crime? Grace's diligent exhuming of murky secrets soon demonstrates that the Bishops' outwardly settled lives had darker corners. And as Grace gets close to the truth, he finds - paradoxically - that it's his own beleaguered private life which is on the line...