The trio at the center of this drama include Susan Strasberg [Rollercoaster] as Penny, Ann Todd as the step-mother and Ronald Lewis as Robert, the hired hand on the estate. They are perfect together and play off of each other extremely well. They keep things interesting and suspenseful scene after scene. Christopher Lee also stars in the small bit part of Dr. Pierre Girrard. He fits the bill nicely and leaves the viewer wishing he had more scenes in the film.
I consider Scream of Fear to be one of the undiscovered gems of Hammer Horror. If you like thrillers, this one is an absolute a must-see. Intelligent. Suspenseful. Surprising. Who could ask for anything more?
For more info check out the film's entry in IMDB.