A definitely dated film, but one that asks the question "nature or nurture?" as relevantly today. In our society, it's still nearly impossible to believe that a sweet eight-year-old girl could possibly be a narcissistic sociopath, capable of killing over an imagined slight or to get what she wants. That this movie was released in 1956 shows that it's a question society has been wrestling with for quite awhile. Can someone be born bad?
Rhoda Penmark (Patty McCormack) was brought up with two loving parents and a reasonable amount of wealth and comfort. She has nearly everything she wants, and is remarkably well-behaved and polite. Her one disappointment is not winning the school penmanship medal.
This is the impetus sets in motion a chain of events that leaves a small boy drowned, and throws the light of suspicion on Rhoda, in others and eventually in her loving mother (Nancy Kelly).
The climactic ending is a surprise, but unfortunately a rather laughable one. I would have rather seen the movie end earlier, where the end seemed to be, or much later to see how the father dealt with the truth.