Pit of Darkness is a 1961 British thriller film, directed by Lance Comfort and starring William Franklyn and Moira Redmond. The film is an amnesia thriller dealing with a man's attempts to piece together a sequence of strange events in which he seems to have been involved during the time of which he has no memory, based on the novelTo Dusty Death by Hugh McCutcheon.
Plot
Safe-designer Richard Logan comes to consciousness on a patch of waste ground with no recollection of how he came to be there. Assuming he must have been attacked and hit over the head, but feeling no apparent ill-effects, he returns home to wife Julie to apologise for being late and tell his story. He is astonished to learn from Julie that he has been missing not for a few hours, but for three weeks. Furthermore, a troubling series of events has occurred during his absence, which appear to point to his involvement in criminal activity. A safe which he personally installed in a large house has been robbed and its contents stolen, with no explanation as to how its supposedly foolproof security mechanisms were so easily overridden. In an attempt to trace her missing husband, Julie has employed a private detective, who discovered evidence implicating Richard of involvement with another woman, and more seriously the private detective has recently been found murdered. Richard enlists Julie's help in trying to recover his memory of the peculiar goings-on of which he has no recollection. He soon becomes aware that he is being trailed by a group of mysterious men. Meanwhile, in his confused mental state he is constantly tantalised by seemingly random and trivial things - a snatch of a popular song or a conversational nuance - which seem to strike a chord with him, for reasons for which he cannot account. He starts to experience flashbacks so momentary and fleeting that they are gone before his conscious mind can seize them. He begins to question the validity of the assumptions on which he is working, wondering if he may indeed have been involved in criminal activity which his mind has blocked out as a defence mechanism, and even begins to doubt Julie's integrity, questioning whether she may have far more knowledge of, and personal involvement in, what has been happening than she is letting on. He is lured to a country house which is blown up. The resulting intrigue finally appears to jolt his memory back into place, and he believes he has found the explanation for what has been going on.