Three siblings find a half boy/ half bat creature in cave in rural West Virginia. The local sheriff then brings Bat Boy to the home of the local veterinarian, Dr. Parker. Bat Boy is soon accepted in the Parker family and raised by Dr. Parker’s wife, Shelley, and her daughter, Meredith. Things get more complicated when Meredith and Bat Boy fall in love and Shelley reveals that she is actually Bat Boy’s mother. Enraged, Dr. Parker leads the town folk in a murderous rampage against Bat Boy.