Cowboy Bebop: The Movie, known in Japan as Cowboy Bebop: Knockin' on Heaven's Door (Japanese: カウボーイビバップ 天国の扉, Hepburn: Kaubōi Bibappu: Tengoku no Tobira, lit. Cowboy Bebop: Heaven's Door), is a 2001 Japanese animated science fiction film based on the 1998 anime series Cowboy Bebop created by Hajime Yatate. Synopsis: A team of bounty hunters track down the perpetrators of what is assumed to have been a bioterrorist attack.

References:
https://en.wikipedia.org/wiki/Cowboy_Bebop:_The_Movie