A remake of the 1982 film, Doraemon: Nobita's Great Demon, which was written by original Doraemon co-creator Fujiko F. Fujio.

One day Doraemon, Nobita, Shizuka, Gian and Suneo were shooting a film as space heroes. When they were shooting the film in the open lot a boy called Aron comes and alerts them of aliens attacking his planet. They agree to help him by turning into real superheroes, but it isn't as easy as it looks.

[Source: Wikipedia]