Dave Snowden (James MacArthur) elopes with wealthy Bonnie Daniels (Lynn Loring), and they break into the abandoned old estate where Bonnie grew up. As they wonder what is behind a locked door on the upper floor, they stumble upon Bonnie's mother, Mrs. Daniels (Gloria Swanson). Mrs. Daniels always protected Bonnie--who was sickly and plain in her childhood--against gold-digging suitors. She annuls the marriage, because Bonnie's true age is only 17. A month later, when Bonnie reaches majority, she rejoins Dave, and they consummate nuptials, but Mrs. Daniels snubs them, and will not release Bonnie's trust fund until she is 25.
http://www.filesonic.com/file/41950933/Alfred Hitchcock - Behind the Locked Door.avi