| Director | William Cameron Menzies |
|---|---|
| Runtime | 80 min |
| Country | United States |
A Scotsman, Gerald MacTeam (Richard Carlson), abruptly breaks off his engagement to beautiful Kitty (Veronica Hurst) after receiving word of his uncle's death. He inherits a mysterious castle in the Scottish highlands and moves there to live with the castle servants. Kitty refuses to accept the broken engagement and travels there with her aunt (Katherine Emery). When they arrive, they discover Gerald has suddenly aged and his manner has changed significantly.
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. Although the friends are equally concerned by Gerald's behavior, they are at a loss as to its cause. 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. There, they find Gerald and his servants tending to a frog-like monster. The monster panics upon seeing the strangers and runs back to the castle, hurling itself from a top-story balcony to its death.
Gerald explains that the amphibious creature was the actual 200-year-old master of the castle, Sir Roger MacTeam. 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. Gerald and his ancestors were merely Sir Roger's servants. The death of Sir Roger releases Gerald from his obligation and he can return to a normal life.