Back in the early 60s, horror films featuring older famous actresses were, for a time, a popular genre. The most well-known is probably /Hush ... Hush, Sweet Charlotte/, but there was also /Strait-Jacket/, which was about a woman released from the asylum after twenty years who returns home, whereupon bodies begin to pile up. Who the killer is is the plot of the story.
Well, /this/ film is about a women who escapes from prison after twenty years and appears to be heading home, where the one girl of the five she kidnapped (killing the parents in at least two cases) who survived still lives. And, sure enough, bodies start piling up. And the question is, who is doing the murders? Because they seem to be awfully ... specific ... to the Girl Who Got Away.
There's also a back story, and things are not at all what they seem.
This isn't the scare-fest or gore-fest some people are looking for. It is a different type of film altogether.
And it is /very/ well done.