Nobita and Doraemon find a giant robot in pieces which they later assemble. It turns out to be a destructive weapon and the gang must save Earth from an imminent invasion.
When Nobita goes diving with Doraemon, a mermaid named Sophia comes close to him and they all befriend her. When they proceed towards her kingdom, they encounter a fight between two opposing tribes.
Nobita and Doraemon use time tree Mochi and catch a big bird, which has been extinct for 500 years ago. To protect the animal, Nobita and Doraemon go to Beremon Island, overseen by a golden beetle named Herakles.
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.
Nobita’s troubled about what to do with his zero test marks once again. A gust of wind scatters his test papers and he falls into a garbage dump trying to gather them together again. There he finds a young withered tree that caught one of his papers and he decides to take it home. He tries to plant it in his garden but gets caught by his mother who doesn’t allow him to grow it.
Doraemon and Nobita discover a mysterious golden ring far beneath the ice in Antarctica, leading them to uncover an ancient, ruined city.
While Doraemon is asleep, a famous thief comes and steals his cat-bell. Without his cat-bell, Doraemon starts to act more and more like a normal cat. In order to stop this, Nobita, Shizuka, Suneo, and Gian have to go and search for his bell, so they go to a factory where all of Doraemon's gadgets are made.
When Nobita turned the world into a world with magic with the what-if-telephone-booth-gadget, He and his world needed to defeat the threat that became reality in this world.
Elmer is told by a traveling cat about a baby dragon who is being held captive and mistreated on the scary Wild Island. Elmer decides to investigate and battles tigers, crocodiles and gorillas in order to rescue the little dragon.