Ah! My Goddess: The Movie (劇場版「ああっ女神さまっ」, Gekijōban "Aa! Megami-sama!"?) is a 2000 Japanese animated film directed by Hiroaki Gōda, written by Michiko Yokote and Yoshihiko Tomizawa, animated by Anime International Company and co-produced by Kodansha, Dentsu, Sega Enterprises, Pony Canyon, Nippon Shupan Hanbai, AIC, MOVIC and Shochiku, based on the manga of the same name by Kosuke Fujishima. The film's theatrical release took place on October 21, 2000. It was also distributed by Shochiku in Japan. In the English speaking world, the film is licensed by Geneon Entertainment in the United States and Canada, MVM Films in the United Kingdom, and Madman Entertainment in Australia and New Zealand.

The movie takes place years after the events of the manga and anime. Celestin, a former mentor of Belldandy, is released by Morgan Le Fay, and erases all memories of Keiichi from Belldandy to use her as a virus to hack the Yggdrasil computer in the heavens. Though the film's main plot is an own canon, many of the plot elements and side-events are based heavily on elements from a wide variety of chapters from Fujishima's original manga.

Source: Wikipedia