An unusually daring "horror" film which isn't that horrific at all, concentrating more on the characters than on a good scare. Church organist Terry is framed for murder when he ventures to the big city to get revenge on Paige, who faked a marriage to Terry's younger sister, Drew, in
order to draw her into a life of prostitution. On the way to his execution, a scientist, Zucco, approaches him and asks for the use of his brain. Having little use for it, Terry agrees--his brain soon winding up in the skull of an ape. The ape-man goes on a rampage, destroying the gang responsible
for the frame-up. Ultimately the ape is killed by the police after killing his last torme...