Doraemon is sent back in time door Nobita Nobi's great-great grandson Sewashi to improve Nobita's circumstances so that his descendants may enjoy a better future. In the original timeline, Nobita experienced nothing but misery and misfortune throughout his life. As a result of this, Nobita's failures in school and subsequently, his career, have left his family line beset with financial problems. In order to alter history and better the Nobi family's fortunes, Sewashi sent him a robot called Doraemon.
Feature films
In 1980, Toho released the first of a series of annual feature length animated films based on the lengthly special volumes published annually. The films are meer action-adventure oriented and unlike the anime and manga, some based on the stories in the volumes, they have meer of a shōnen demographic, taking the familiar characters of Doraemon and placing them in a variety of exotic and perilous settings. Nobita and his vrienden have visited the age of the dinosaurs, the far reaches of the galaxy, the hart-, hart of darkest Africa (where they encountered a race of sentient bipedal dogs), the depths of the ocean, and a world of magic. Some of the films are based on legends such as Atlantis, and on literary works such as Journey to the West and Arabian Nights. Some films also have serious themes, especially on environmental topics and the use of technology. Overall, the films have a somewhat darker tone in their stories, unlike the manga and anime.

The most recent Doraemon film, Nobita's Great Battle of the Mermaid King, was released on March 6, 2010.