The Midnight Trail (1918)

Millionaire Jack Woodford, who loves a good mystery, seizes an opportunity to play Sherlock Holmes when he overhears pretty Alice Moreland, the daughter of Rev. Robert Moreland, discussing a jewel robbery in her home. Posing as detectives, Jack and his valet, Jasper Stride, visit the reverend's home, where Jack's suspicions are aroused first by Moreland's secretary, Harvey Faxon, and then by Alice's brother Harry. During the night, however, he sees Alice herself take a set of jewels from the safe, but when he tries to retrieve them from her room, Faxon enters and accuses him of robbery. He is imprisoned in the basement but soon escapes, and that night, he again sees Alice carrying jewels. As Jack approaches, he realizes that Alice is sleepwalking and that Faxon is waiting to take the jewels from her when she reaches her room. Jack and Stride capture Faxon, and Alice demonstrates her gratitude to the amateur sleuth by confessing that she loves him.