Set in the 19th century, the plot centered around a man (Harold Lockwood) who is falsely accused murder. The Other Side of the Door was shot in Monterrey, Mexico.
A wealthy young woman, Agnes (played by Burton), is loved by the identical twin brothers Clyde and Ward Kingsley (dual role played by Russell). She marries Clyde and he immediately begins squandering her fortune. When the money is almost gone, Clyde comes up with a plan to collect on his life insurance policy. As his brother, Ward, who still loves Agnes, is terminally ill, he persuades him to take his place so the insurance company will believe that Clyde has died instead of Ward.