This was the final episode of "Thriller"'s first season. It is the least effective but it is still pretty good and has more to commend it than first seems.
The action starts with the sudden and mysterious death of Tony Mansell's wife. Some months later he unexpectedly decides to write to Modernmates, a marriage bureau. Almost as soon as he sends the letter he receives a reply from the seductively-voiced Clara Panton. When they meet they immediately hit it off. That same afternoon Tony asks her to marry him.
The marriage is a happy one. However Tony's housekeeper and secretary are both suspicious of Clara. There are a few strange events and small accidents. However later things take a much more violent turn. Tony's secretary feels she must investigate while he seems totally unaware of the terrible danger he faces.
This installment has some very powerful elements but it doesn't really seize the imagination or frighten in the way that some other supernatural outings such as "Nurse Will Make It Better" and "A Place To Die" do. This is chiefly due to the central character of Clara. Clara, played by Diane Cilento, can be very disturbing, notably when she is casting her spells (these scenes are very skilfully directed). However her over-the-top dress, make-up and jewellery - she literally rattles at times - make her hard to take entirely seriously. A more understated look would have helped. An interesting comparison is with Diana Dors's witch in "Nurse" who was a far more unsettling figure. Maybe the difference is partly due to the acting, although Cilento turns in a decent performance all the same.
The casting perhaps is the main reason for the failure to turn a good episode into a great one. All the performances are sound but nobody really excites. The story is certainly a strong one from the impressive Terence Feely. The climax is quite good but hampered by mediocre special effects. Another notable feature is a brief but important role for William Dexter as an eccentric witch-craft expert with a broad Welsh accent - very unusual to hear any accents in this sort of production.
To conclude, while this would certainly not be my first choice of "Thriller" viewing it does have considerable merit and is worth just over an hour of your time if chance arises.