The United States Constitution is stolen by a revolutionary and agents James West and Artemus Gordon are sent by the government to recover it. Arriving at a Mexican border town, the agents penetrate an installation under a fortress to find the priceless document. When the agents find the revolutionary, he demands one million dollars for what is later discovered to be a forgery of the Constitution. Before forcing the revolutionary into a pool of acid, they are told a riddle that leads them to the hiding place of the real document.

Sent by President Grant, Jim West travels to Fort Savage and finds outlaw Sean O'Reilley in charge trying to incite a revolution in Canada. Gordon infiltrates the revolutionaries and finds West held captive.

West and Gordon accompany the Ambassador to Mexico who's trying to establish diplomatic ties with them which has not been going so well. They attend a festival wherein the Mexican President makes an appearance while riding in his carriage. West sees a sniper so he throws a wrench in the plan. He and Gordon try to get the shooter but he gets away but they get the his accomplice whom they recognize as an American criminal. They keep the Mexicans from finding him because as mentioned the Ambassador's mission has not been going well and if word gets out that an American ...

Special agents West and Gordon are sent to the mortuary to identify the body of their arch enemy, Dr. Miguelito Loveless. A mourner at the morgue takes a key from the wrist of the corpse and West traces it back to a safe deposit box containing instructions to contact an attorney. When West makes contact, he also meets Dr. Leibknicht, the look-alike relative of Loveless.

West and Gordon are sent to escort a horse, a gift from President Grant, to the Mexican government. The horse is stolen, however, and the two work to recover the lost gift before a diplomatic incident occurs.

A valuable samurai sword being returned to a Japanese prince by the United States' government is stolen and must be found by Jim and Artemus before the prince leaves the next day.

Jim and Arte go undercover to overturn a hanging verdict unjustly given to an innocent man.

James West travels to a museum to meet Johnson for the search of Montezuma's lost treasures. Along the way to the Aztec location, they meet Artemus Gordon, disguised as a desert rat, who is hired as a digger. The expedition discovers an Aztec temple.

When masterfully forged bills appear in circulation, West and Gorden must catch the forgers to prevent the collapse of the U.S. economy from a flood of nearly perfect counterfeit bills.

After witnessing the total destruction of a town called Tonka Flats, agents West and Gordon receive a further threat to destroy the city of Denver. Demanding a ransom, Dr. Horace Humphries, alias "The Falcon", plans to fire a single shell from a falcon-shaped cannon toward this western city. West and Gordon go to an underground hideout in search of the destructive cannon. But once inside, the agents discover syndicate leaders from foreign countries bidding to purchase the massive weapon for their own use.

A band of outlaws threatens to destroy the town of New Athens. West and Gordon are the town's only hope of survival.

Jim and Arte uncover an unscrupulous plot devised by an ambitious dictatorial governor who has plans to become President of the United States.

Elisha Calamander, a thief of priceless art for wealthy clientèle, discredits agent West, who is severely punished by the government with a discharge from the special forces. Calamander offers West $50,000 to help with a special secret assignment.

West and Gordon work to escort Draja, a Bosnian count, to Washington for extradition. A disguised Gordon takes his place on the train, while West and the real Draja take a back route to keep the count from recovering a hidden stash of gold. They soon find a gang of reward-seeking vigilantes on their trail, while Gordon's cover is threatened by the appearance of an old friend of the count.

Jim and Arte decipher the meaning of a dying man's last words in order to stop an assassination attempt on the governor.

To save the Indians from being slaughtered by the cavalry, West and Gordon must keep the peace and uncover who is behind a plot to provoke war with the Indians.

West and Gorden investigate a plot by an international cotton syndicate to decimate America's cotton crops using boll weevils.

The Vipers, a band of outlaws, have been pulling off raids across Kansas towns. A clue leads West and Gordon to the quiet village of Freedom, where they meet a straight-shooting sheriff and a mayor who will stop at seemingly nothing to become governor. Gordon goes undercover and finds the plans to the Vipers' get-away wagon, while West discovers the secret entrance to the outlaws meeting place.

During Mardi Gras in New Orleans, agents West and Gordon look for the cruelest former commander of a Civil War prison who has been a fugitive from justice for the abuse of prisoners. They meet a young girl who leads them to Hazard, her legless father and victim of the prison commander. Hazard and his men are after the commander as well, but their real goal is to find a shipment of one million dollars that disappeared after arriving at the prison.

Jim and Arte unknowingly become a part of a bizarre revenge plot involving mistaken identities.

Revenge, jealousy and a rivalry between two doctors result in dastardly human experiments when James West comes upon a voodoo sacrificial killing. As West shoots his gun into the air to stop the ritual, the zombie-like participants turn and walk away. West is then attacked by a huge man named Tiny John, but as the agent shoots the man in the heart, Tiny John simply turns away and heads for the swamp. While the agents investigate further, they learn why the people are in a trance and discover the real reason behind the doctors' contempt for each other.

Special agent West is charged with the responsibility to transport the state's only supply of a smallpox vaccine to safety. On the way, West's stagecoach is ambushed by a gang, led by Silas Crotty, who steals the serum and shoots West as he tries to protect the vaccine. When West awakens in the field, he has lost his memory and his identity.

Jim and Arte uncover a secret revenge plot involving inhuman medical experiments.

Jim and Arte stop a plan to assassinate President Grant devised by a bitter officer who was stripped of his command.