As the Wild Wild West begins, we meet U.S. Army Captain James West, who tends to solve problems with force, and U.S. Marshal Artemus Gordo, who tries to solve problems with his inventions and ingenuity, both hunt for Confederate General “Bloodbath” McGrath. They believe he was responsible for a massacre of former slaves. In a brothel featuring one of many drag scenes the two realize they are both hunting McGrath.
Eventually, the two reluctantly work together to solve the mystery of the massacre. They soon find out that Dr Arliss Loveless, an ex-Confederate mad scientist in a steam-punk wheelchair, is their real enemy. While at a ball thrown by Arliss, they meet the film’s love interest, Rita Escobar, and rescue her. After many bad jokes about slavery, the group escapes.
Arliss uses McGrath’s troops to test a tank-like weapon, and has them massacred. McGrath is close to death, and he informs West that Arliss was responsible for the massacre that killed his parents; not him.
The group tries to find Arliss, but he ends up chasing them on railroad tracks. Eventually, he does capture them, and then he makes his plan known to have the US surrender to his cabal.
Spiders, including costume and set choices strangely facinate Arliss. At the appropriate time, he reveals a giant steam powered mechanized tarantula/weapon which he then marches to President Grant’s location in Utah. He takes him, as well as Gordon, who is disguised as Grant. On of Arliss’ female minions shoots West, and appears to be dead. He isn’t, of course.
Gordon and West build a flying machine to take on the spider as Loveless attacks a town. They are able to board the spider and defeat Arliss.
Grant promotes Gordon and West to the first two secret service positions in history. Gordon and West want to talk up Rita again, but she reveals her ‘father’ she was looking for the whole time was actually her husband, and she was just using the two of them. Bitch move Rita.