The fourth spiritual-procedural mystery featuring the Rev. Merrily Watkins as exorcist Electricity pylons now mark the old Roman road from Gloucester to Monmouth. Midway along it is the unlovely village of Underhowle, confronting a new prosperity... but also home to a man the police have identified as the killer of several young women. But for the local exorcist, Rev. Merrily Watkins, this truth might never have emerged -- but is that the whole truth? For, as the police hunt for more bodies, Merrily is increasingly worried that the detective in charge might have become blinkered by ambition. Meanwhile, Merrily has more personal problems: like the anonymous phone calls... the candles and incense left burning in her church... not to mention the alleged angelic visitations on which many will heap scorn. It is her musician boyfriend Lol who follows an unexpected path into the mind of the confessed murderer, while Merrily herself must quell revulsion in scrubbing away the psychic stain left by a dead monster.