A film projectionist longs to be a detective, and puts his meagre skills to work when he is framed by a rival for stealing his girlfriend's father's pocketwatch.
Two men, one of them a villainous hypnotist, contend for the same woman, unaware that she suffers from dual personality disorder.
A world-famous pianist loses both hands in an accident. When new hands are grafted on, he is horrified to learn they once belonged to a murderer.
A gang of crooks are employed to get possession of valuable papers of international importance, held by the French Ambassador, Vicomte de Jarlais. They are also instructed to get the Ambassador out of the way and make it appear that he has committed suicide. His mysterious disappearance arouses the United States Secret Service officers
Police headquarters has been plagued by a series of robberies, culminating in the theft of a priceless necklace smuggled from Europe. The detectives are on the track of a gang led by master thief Ramon Mordant and his accomplice known as "the Face" because of his twisted and hideous countenance.
Louis and August Siever, the twins sons of a German father and American mother, are traveling in Europe when war breaks out. August joins the Kaiser's army, but Louis, a supporter of the United States, is practically made a prisoner in Berlin for a year while he tries to prove his American citizenship. After a violent confrontation with Louis, August steals his brother's passport and leaves for New York with Gerda Anderson, a German spy.
Lois Fox, upon whose shoulder is branded a Chinese idiograph resembling the letters "A. Y.," is rescued from a gang of Chinese ruffians by Brice Ferris. His servant Ming, in attempting to steal from her finger a ring that bears a mysterious green seal, is killed, and soon afterward a stranger named Strang arrives, also in search of the girl. Despite Brice's efforts to protect her, Lois is abducted and taken to the headquarters of Lao Wing, the leader of a secret Chinese society known as the Tong.
Old Silas Blackburn, a wealthy recluse, lives alone with his butler and his ward Katherine. One night, Katherine discovers Silas murdered in the room where three generations of Blackburns have mysteriously died. Silas' grandson Robert, whom Katherine loves, comes to visit the next day, suffering from amnesia.
Wealthy diamond collector Larry Hanrahan is given the opportunity to assist the beautiful, jewel-bedecked woman he admires in a Broadway café when she and her guardian are attacked by robbers. Larry is invited to visit the grateful pair, Col. Paul Gascoyne and his ward Adrienne, at the colonel's laboratory, where he is introduced to Wintermute, a chemist who produces imitation diamonds. In return, Larry asks them to view his priceless diamond collection. Although he has fallen in love with Adrienne, Larry is forced to believe that she is a thief when he is robbed by a woman wearing Adrienne's scarf. Larry finds his jewels in Gascoyne's house, but before he can escape, a group of thugs overpowers him. Adrienne assists him in contacting the police, who arrive in time to capture Gascoyne and his gang. Badly wounded, the colonel confesses that Adrienne has been his innocent dupe, whereupon Larry happily takes her to his heart.
At a party thrown at the Metcalf estate, the Marquise D'Irancy's Sultana diamond disappears when the lights go out during a power failure. Suspected of the crime is William Kirkland, the wastrel son of the wealthy Kirkland family, but William's sister Diana comes to his defense. Aiding her in the investigation is Clamp, a wandering peddler.
A man and two women, suspected of stealing bonds, are traced to a country hotel. While Judith, one of the women, is out horseback riding, the other two, Walter and Vera, are arrested. When, during a storm, Judith is injured in a fall from her horse, Boone Pendleton comes to her rescue. Soon the river becomes impassable, and they are trapped in Boone's cabin, where the two fall in love.
London. A mysterious serial killer brutally murders young blond women by stalking them in the night fog. One foggy, sinister night, a young man who claims his name is Jonathan Drew arrives at the guest house run by the Bunting family and rents a room.
Edith Sturgis, the daughter of a judge, returns from studies abroad to find her widowed father remarried. The new Mrs. Sturgis does not reveal that she has a son Dick, once unjustly jailed by Judge Sturgis, but now working as a reporter while still maintaining an association with the Brownlow gang. Quarrelling with her stepmother, Edith leaves home, meets Dick and falls in love.
Holmes and Watson match wits with an opera star intent on blackmailing a king.
Henry Egbert Xerxes' big chance as a cub reporter comes when he is assigned to track down a gang of counterfeiters which gathers regularly at the Red Dog Inn. As he leaves the office, Henry witnesses a girl being dragged into a cab -- the same girl he had seen that morning passing counterfeit money. Henry follows, but on overtaking the cab, he finds it empty. At the Red Dog Inn, he discovers that the girl is being held captive. After a series of rough and tumble adventures with the resident thugs, he and the girl escape, after which he rushes home to write up the story. When it fails to appear in print, Henry storms into the city room only to discover that the entire business was a hoax, intended to test his reporter's instincts.
Young London realtor Leonard Tavernake becomes involved with two sisters, one good and one evil, which leads to much melodrama but things work out in the end.
Rosalind Joy (Helen Foster) is an heiress who has inherited a South Seas island known as Pleasure Island. A hidden cache of gold is allegedly buried on the island, which has several haunted structures. Rosalind's uncle, Spring Gilbert (Al Ferguson), wants the gold for himself and declares he will stop at nothing, not even the death of his niece, to get it. Rosalind, meanwhile, is befriended by Jerry Fitzjames (Jack Dougherty), a playwright. Unfortunately, Jerry has only recently escaped from a psychiatric hospital. Although he swears to protect Rosalind, she doubts Jerry's sanity. The two lovers race against Uncle Gilbert (who has set several traps for them) to find the treasure. In the end, Rosalind and Jerry are aided by the "Phantom Rider," a spectral horseman.
A demon, a reaper, and the ghost of a prostitute read gothic short stories and act them out.
John Stonehouse (William Russell) checks into a hotel, intending to commit suicide. But instead he winds up helping a girl, Gilberte Bonheur (Fritzi Brunette), out of a jam. He finds her bending over a man who she has apparently killed, and since he's about to kill himself anyway, he offers to assume the blame. Throw a valuable emerald into the works, and the fact that the dead man suddenly comes back to life, and Stonehouse -- not to mention the audience -- becomes thoroughly befuddled by it all. Everything clears up, however, when Gilberte gives him a theater ticket -- it turns out that everything he went through was the plot to a stage play, enacted in real life by the actors. The critics roasted the play, saying it wasn't true to life, and this was their proof that the situations really could happen. Gilberte retires from acting when Stonehouse proposes.
A woman's cheating husband is murdered at their country estate, and suspicion immediately falls on her.