[1] It was to be the second 3-D film designed and directed by William Cameron Menzies, known for his very "dimensional" style (e.g. many shots focused in layers).

A Scotsman, Gerald MacTeam (Richard Carlson), abruptly breaks off his engagement to beautiful Kitty (Veronica Hurst) after receiving word of his uncle's death.

After a series of mysterious events in the castle and its hedge maze, they invite a group of friends there, including a doctor, hoping they can help Gerald with whatever ails him.

One night, Kitty and her aunt steal a key to their bedroom door (which is always locked from the outside) and sneak out into the mysterious maze.

Sir Roger never progressed beyond an amphibious embryonic stage, causing him to develop into a frog-like creature whose only pleasure was swimming in the castle's pond.