The Japanese anime series Cowboy Bebop consists of 26 episodes, referred to as "sessions". Most episodes are named after a musical concept of some sort, usually either a broad genre (e.g. "Gateway Shuffle") or a specific song (e.g. "Honky Tonk Women" and "Bohemian Rhapsody"). The show's first run, from April 3 until June 26, 1998, on TV Tokyo, included only episodes 2, 3, 7 to 15, 18 and a special. Later that year, the series was shown in its entirety from October 24, 1998 to April 24, 1999, on the satellite network Wowow.
In the United States, the series was aired repeatedly after late 2001 on Cartoon Network's Adult Swim programming block. In its original run on Adult Swim, episodes 6, 8, and 22 were initially skipped due to their violent and destructive themes in wake of the September 11 attacks. By the third run of the series, all these episodes had premiered for the first time.
The show takes place in 2071 and follows a group of bounty hunters who hunt criminals on their ship, the Bebop. The main characters include Spike Spiegel, a laid-back former member of the Red Dragon Syndicate (a criminal organization) and hotshot ace pilot; Jet Black, a retired cop and the owner of the Bebop; Faye Valentine, a gambling-addicted amnesiac who always finds herself in financial debts; Edward Wong Hau Pepelu Tivruski IV (nicknamed "Ed"), an eccentric computer hacking prodigy from Earth; and Ein, a "data dog" as the group's pet.
A film was released in Japan in September 2001, titled Cowboy Bebop: The Movie (known in Japan as Cowboy Bebop: Knockin' on Heaven's Door). The film takes place between episodes 22 and 23.
Set between episodes 22 and 23 of the original series, the story begins a day before Halloween. Spike Spiegal and Jet Black intercept a store robbery to detain the crooks and collect the small bounty on their heads. Faye Valentine is in the middle of chasing her own small bounty when she's stopped by a tanker truck explosion. She sees the driver escape the explosion unharmed but he does not match her bounty's description so she returns to the Bebop. The others are watching the news coverage and are interested in the 300 million bounty on the person behind the tanker explosion.
Spike takes to the streets to find "beans" (specific information on the explosive bio hazard). He ends up in the Martian Moroccan district where a mysterious man gives him a large vase. Jet meets an old contact at the ISSP and only learns that the police force aren't interested in investigating due to petty corruption but the tanker explosion was traced back to Cherious Medical, a pharmaceutical company who never reported the truck missing. With Faye's lackluster help, Edward and Ein identify the driver who survived the tanker explosion as Vincent Volaju, a soldier who is listed as deceased. Ed finds a blue marble in Spike's vase.
After some examination, it's determined the marble is connected to the bio hazard explosion, hiding a mutated lymphocyte inside. Ed and Ein manage to track down the hacker that Faye had been chasing and they tip her off before joining some kids to trick or treat. What no one knew was that the hacker had been collaborating with Vincent who found no more use for him and kills the hacker by shooting one of the many marbles in his possession. Faye finds the hacker hacking up a cough and dropping dead, then she becomes infected but is subdued by Vincent. Spike managed to infiltrate Cherious Medical and planted a locator on a female employee, Elektra Ovirowa, following her to a train where he fights Vincent but ultimately ends up getting shot and thrown off the train into the river below. Elektra corners him but doesn't shoot Vincent, seemingly knowing him. He releases a bomb with the bio hazard which affects every passenger on the train except her.
Jet is fished out of the river by an old Shaman friend and he's taken back to the Bebop to recover. After some computer hacking by Ed, they find out the supposed pharmaceutical company was a cover for building protein nanobots, which were mimicking the lymphocytes, an were meant to be the ultimate weapon. While looking for the man who sold him the vase, Spike finds out the organic microscopic robots were tested on soldiers but so was a vaccine, which was only injected into Vincent who went AWOL and insane. He relates much of this information to Faye, who was inoculated with his blood and is now unaffected by the nanobots. Elektra is discovered to also have the vaccine in her blood, meaning she was also in contact with Vincent. Both she and Spike are captured by soldiers who work for Cherious Medical. In their cells, Elektra explains how she fell in love with Vincent while they were fighting on Titan. Vincent explains to Faye his plan to infect the world with a mutated version of the nanobots, killing everyone. He leaves her tied up to get his Halloween plan in motion.