Sewashi and Doraemon find themselves way back in time and meet Nobita. It is up to Doraemon to take care of Nobita or else he will not return to the present.
Doraemon and his friends travel to ancient Japan where they meet Kukuru. When Kukuru tells them that his tribe has been enslaved by Gigazombie, Doraemon decides to help him.
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.
