Agents West and Gordon are notified by another agent about an assassination plot against President Juarez of Mexico. Later, they find the agent dead with a knife in his back through a flyer for the Echo Amusement Park. When West arrives at the deserted amusement park, he meets Count Manzeppi, master of trickery and corruption. Manzeppi captures West and force him to help kill the Mexican President. First, he must kill his partner and best friend, Artemus Gordon.
The Indian Commissioner of the Pawnee Indians recruits James West to investigate the strange occurrences at the reservation. In his search, West is bitten by a cobra snake rendering him unconscious. When he awakens, Jim finds himself in the palace of the Maharajah of Rampor, also known as Mr. Singh.
Agents West and Gordon are engaged to rescue an Indian Chief's abducted daughter before the Indians retaliate. The agents learn that the miniature Dr. Miguelito Loveless, responsible for the kidnapping, has a plan to rule a land of little people, with the help of a powder he invented to reduce the size of people. During the rescue mission, Loveless shrinks Jim and the Indian Princess to a height of six inches, leaving them to defend themselves from the mad doctor's now gigantic cat.
Dr. Faustina and her mute servant, Miklos, have transformed a corpse into a duplicate image of Jim West. When they bring the corpse back to life, Faustina's plot is to have the West look-alike gain entry to a meeting of the President's cabinet to kill four of the members.
Agents West and Gordon are called to investigate a mysterious Confederate night rider who comes to the ranch of Carl Jackson, its wealthy owner. When the agents are charged by the ghost rider, they discover that the rider's appearance coincides with the stable boy's eerie flute music. West and Gordon soon learn that Jeremiah, the stable boy, has been living with a secret since his childhood, but others are trying their best to keep the agents from discovering the truth.
Agent James West is protecting a shipment of gold en route to an Arizona town when he sees a flaming light in the sky and hears a loud crash. West and the townspeople discover that a spaceship has landed and they witness three green women, resembling Martians, coming out of the ship. Apparently, the women want to trade the precious gems on their clothing for gold, which will be used as fuel for their spaceship's return trip. Artemus Gordon, posing as an expert jeweler, senses a scam as he examines one of the gems.
While on vacation, West and Gordon wander into the town of Justice, Nevada. After an unexpectedly exciting greeting by the citizens, they start to notice an unusual number of infamous international criminals around town. Artie goes undercover to investigate this mysterious gathering while Jim gets into trouble confronting the villains directly.
The assignment for James West is to find a fellow agent who is imprisoned on Devil's Island. Getting imprisoned himself, West is given lashes and sent into a pit where he finds Vincent Reed, the agent he was to free.
While at the Mermaid Bar, Agent James West is shot with a blow dart by a woman disguised as a Mermaid. When he comes to, West finds himself aboard a ship, where he meets an unusual woman with a mysterious compact. Suddenly, the ship is attacked by a fire breathing dragon and ship explodes. After floating to shore, Jim meets Arte and they unveil the secrets of a new weapon: a dragon-like torpedo attracted to a homing device in a woman's compact. Together they must find the weapon before a government ship, loaded with a cargo of explosives, arrives in the San Francisco ...
As they ride through the forest, Jim West and Artemus Gordon notice the unusual lack of vegetation and animal life. They are suddenly approached by a giant knight who takes them to a large tent. There, West and Gordon meet a miniature Robin Hood, who is really the evil Dr. Miguelito Loveless in disguise. Loveless wants to control the Indians as he starves them by killing their food with his lethal green powder.
Agents West and Gordon are assigned to guard foreign dictator Colonel Pellargo but are foiled by a clever assassin who himself shows up dead only a few days later. However, the disappearance of a local Irishman into Fabian Lavendor's funeral parlor piques the agents' curiosity -- and the cut-and-dried assassination becomes a far more complex intrigue.
Agents West and Gordon are sent to transport a prisoner to the hospital after the prisoner spent nearly thirty years in solitary confinement for treason. Looking for a place to spend the night, the men come upon a deserted mansion whose doors mysteriously swing wide open for the travelers and slam shut once they enter. As night approaches, the men begin to hear a crying woman but they can not find its source.
Special Agents Jim West and Artemus Gordon meet a mysterious woman with a toy chicken who has important information about the dastardly Count Manzeppi. West and Gordon notice the Count, disguised as an organ grinder, outside their window, when a monkey tosses in a smoke bomb. When the smoke clears, the woman is gone but the toy chicken remains. Manzeppi is after the chicken which contains the mystical Philosopher's Stone. The stone will turn anything near it to gold in the light of a full moon.
By order of President Grant, Agents James West and Artemus Gordon must bring Russian prisoner Rimsky to Vladivostok, Siberia, in exchange for American Vice Consul, Millard Boyer. When he tries to escape, Rimsky falls to his death forcing Gordon to disguise himself as Rimsky to complete the exchange. The Russian contact arranging the exchange has West and Gordon imprisoned with the Vice Consul instead. There, they learn that Rimsky should have returned with 5 million dollars in extortion money from wealthy Russian immigrants. Now, the corrupt Russians are waiting for ...
To warn some of the country's wealthiest men about recurrent murders, Agents West and Gordon visit Curtis Dodd, who could become the next victim. Dodd, who is playing the piano, is killed as a lethal spear is fired from the piano keys. Through a series of clues, West and Gordon realize that murdered men were all married to younger women whose marriages were arranged by matchmaker Emma Valentine.
Jim and Arte investigate the early predictions of a friend's death. Before they can warn the next victim, they discover a plot underway to murder all the world leaders and replace them with look-alikes.
Agents West and Gordon are guarding a museum containing the famous Herzberg jewels but someone still manages to steal the gems. Afterwards, a famous painting of Western scene is removed from the museum by its wealthy rancher-owner. Gordon becomes suspicious and notifies West who discovers that the rancher is partners with Miguelito Loveless, the evil inventor-doctor.
President Grant wants to go to Gibsonville to dedicate the statue of an officer under his command during the Civil War. James West travels ahead to ensure it's safe for the President. West finds Gibsonville is now a ghost town and is experiencing an "epidemic" of broken necks. The few residents left are seeking buried gold -- and the number of bodies is rising.
The miniature maniacal Miguelito Loveless is landing his bandits into small bank robberies, then he burns the money. It seems Loveless has bigger plans and is only using these stunts as training for his gang. When one bandits spends some of the charred money, agents West and Gordon are sent to investigate. West follows the clues back to Loveless who brags about his big plans by showing West his training models. An arsenal, a prison and a U.S. Treasury Office are his real targets!