Because the monkey king is only a legend, Nobita and Doraemon have decided to go back in time using the time machine and make a fake one and show Gian, Shizuka, and Suneo to prove that they are right.

Dorami-chan: Wow, The Kid Gang of Bandits / The☆Doraemons: Strange, Sweets, Strange? / Doraemon: Nobita's the Night Before a Wedding Nobita's the Night Before a Wedding ...

Doraemon the Movie: Nobita's the Legend of the Sun King (movie 1-21) as Nobita Nobi (Spain dub; Catalan dub) Doraemon: Doraemon Comes Back (movie) as Nobita Nobi (Catalan dub) ...

Nobita's New Great Adventure into the Underworld (movie 2-02): Broadcaster Doraemon the Movie: Nobita's the Legend of the Sun King (movie 1-21): Broadcaster ...