When Sister Joan of the Order of the Daughters of Compassion is transfered to the convent in Cornwall she goes wth instructions from the Mother Superior to solve the puzzle in the last letter of a dying nun. On the surface, all is sweetness and light in the convent on the moors, but it does not take Joan long to detect that there are som ugly shadows lurking beneath and some very suspicious circumstances to be explained. There is the novice who vanished, and the statue that doesn't fit, and the accident that might not have been an accident at all. And who is the young man hiding in the bracken? In an atmosphere of silence, prayer and increasing menace, Sister Joan, a natural rebel, tries to discover the truth and set it right without violating the vows she has taken. This mystery novel is the first in a series about a modern young woman who has chosen to live under medieval discipline, and finds that only too frequently her two worlds collide.

Evil has crept into the peaceful lives of the Daughters of Compassion. At first there are only small signs of its presence. The unnatural docility of Sister Joan's pupils at the little convent school on the moor. The disappearance of holy water, candles, and flowers from the convent chapel. The midnight flight of a beautiful au pair from the home of one of Sister Joan's students. With old Hagar the gypsy's warnings of malignant and imminent danger confirming her own deep alarm, Sister Joan begins gently to probe, seeking among her students and their families for the sources of the darkness that threatens this remote corner of Cornwall. And when a handsome adolescent boy inexplicably vanishes, she knows a killer is not far away. In a race with time and death, she pursues an evil as old as the human race....

All is not well on beautiful Loch Morag in Scotland, where Sister Joan is resting at a spiritual retreat. Children make signs to ward off the evil eye whenever she passes. She suspects she is being followed. And in the dark crypt, where the bodies of the dead remain partially preserved, she feels the touch of a live hand. A tragedy from the past still grips Loch Morag. But that is nothing compared to the evil in the present, when a sudden storm reveals murder - and Sister Joan must abandon her solitude to ferret out a killer. . .

Sixteen-year-old Valerie vanishes from home in the small hours clad only in her robe and slippers. Three days later, Sister Joan finds her body abandoned in the convent's little Moor Schoolhouse. The dead girl is dressed in wedding white. A garland of leaves encircles her head and a thin red line runs round her neck. Valerie has been strangled. Sister Joan's feelings are mixed when her prioress bids her to assist in the investigation of this eerie crime. But when another young Catholic girl is similarly murdered, she vows to do her utmost to help Detective Sergeant Mill find the murderer. The faster the better, for the killer is assuredly mad-and now seems fatally attracted to Sister Joan's own tranquil, unprotected Cornwall convent....

As the Lenten season of Penance is observed in the Convent of the Daughters of Compassion, Sister Joan finds herself struggling with her less-than-Christian feelings toward two very prickly personalities: the serious and rather stiff Father Timothy and the dour Sister Jerome. Soon, however, she finds herself wrestling with a larger transgression - murder. When the rectory housekeeper is found dead of a pill overdose, Sister Joan refuses to believe the police's suspicions of suicide - and an accident seems equally unlikely. A sudden rash of corpses appears to bear out her theory. Now as she grapples with her conscience and her vows during the holy season, the fearless nun sets a trap for a killer... but she may well find herself caught in an unholy - and deadly - snare.