Frankenstein’s (Peter Cushing) diabolical plan is, in the cause of science, to preserve the medical knowledge of a brilliant but insane surgeon. This he’ll do by murdering the medico, removing his brain and inserting it in the body of a kidnapped man.
With the help of two young accomplices (a doctor, Simon Ward, and his girl friend, Veronica Carlson), drawn into the plot because Frankenstein is blackmailing them over a drug robbery offense, the mad scientist is hijacked from an asylum, operated on and the brains switched.
The film is a good-enough example of its low-key type, with artwork rather better than usual (less obvious backcloths, etc.), a minimum of artless dialog, good lensing by Arthur Grant and a solid all round cast.