Written shortly before his famous novels How Green Was My Valley and None But the Lonely Heart, Llewellyn's play - concerning an outbreak of anonymous poison-pen letters that destabilise a small rural community - was first presented at Richmond, near London, on 9 August 1937.

A West End production, using a revised text, opened at the Shaftesbury Theatre on 9 April 1938, moving to the Playhouse in July and the Garrick in August, achieving in all 176 performances and closing on 10 September.

"[4] Latterly, however, it has been described by film historian David Quinlan as a "slow, sordid but striking dark drama"[5] and by Raymond Durgnat as "a bleak story prefiguring Clouzot's Le Corbeau.

Soon the entire village is overtaken by suspicion and paranoia, and fingers start to point at Connie Fateley (Catherine Lacey), a shy young seamstress who lives alone and does not tend to socialise.

David now starts to receive letters detailing Ann's alleged infidelity, and unstable villager Sam Hurrin (Robert Newton) is targeted with information that his wife Sucal (Belle Chrystall) is dallying behind his back with local shopkeeper Len Griffin (Edward Chapman).

The investigations lead in a surprising direction, towards Mary, the vicar's sister and a respected community member who has managed to hide a severely disturbed mind behind a mask of caring efficiency.