Nobita and Doraemon remove the barriers. Doraemon initially refuses but watching on television about treasure hunt accepts it. Doraemon remembers it is like a 20th century game. Rebel attacks them again and breaks the entire base and Doraemon and cash fall into its stomach and Cash tells Doraemon we will die. Separated, they face real pirates and a dangerous secret. A pirate follows a treasure box and it is actually is a trap and stones fall on them. They take the dolphin and get out the island.
Jack and Betty see their father. The time patrol captures cash. Doraemon and others talk about Nobita and by evening they reach the treasure island. Doraemon and Nobita fall on the top of the tower and fall on to the room of cash knocking him out. A gadget which tells truth pinches the stomach of the monster and then Doraemon and cash are thrown out. Then the captain of the ship talks to them but cannot understand their language.
And so, their adventure begins. And so, with the help of Doraemon, Nobita and the rest of the gang set sail on a ship to find treasure on an islands. The pirate party starts searching for them. He throws a knife at Nobita's feet but to kill a poisonous spider. Nobita points at a point randomly and it shows to have treasure. The search for documentation about the sea for a school work will make the magic door of Doraemon open and take Nobita to Shizuka, Gian and Sueno in the deep ocean. Nobita and doraemon go to the top while others go inside.
Then Suneo learns to use it and suddenly rebel the monster appears and they fire a missile to make it unconscious. A small boy shouts for his father who is gone for the treasure. The remaining people continue forward and find the treasure at the centre of a pool. Unable to endure the midsummer heat, Doraemon transports Nobita and his friends to a huge iceberg floating in the South Pacific. Gian accidentally presses cannon button and it fires the ship of Doraemon.
They are introduced to cash. Ruffin comes to their rescue with her friends and saves Shizuka. Doraemon has only a few gadgets left and uses the translator and they understand each other. All of them get on the pirate ship. But now the group must fight for survival as Doraemon faces the crisis of the entire Earth freezing. He tells them that Dr. They enter a cave behind a waterfall and start crossing a bridge when suddenly it falls and some of them fall off.
Doraemon watches doctor experimenting on the dolphin. A fight breaks out on the deck and Shizuka is attacked and is saved by Betty. They jump onto a ship. They plan and split into two and one will save the dolphin and others to save the other pirates. He turns back to human underwater and nearly drowns. He tells doraemon that he wants to go on a treasure hunt.
They start reading about the sea. The travel towards the waterfall. Upon closer examination, they determine that the ring was buried in Antarctica 100,000 years ago — before people could have lived there. The dolphin takes jack and nobita through a river and to deep inside the jungle. No time to lose, our friends must find a way out.
Nobita and Doraemon set sail for a treasure island, but somehow they travel back in time! Cash release a rhino-croc which attacks them it hits and some rocks are broken. Everything is fine until it grows up. It makes a huge hole and the base starts sinking and ruffin calls time patrol and all of them escape outside. But, nothing is ever impossible for Doraemon and his magic tool. Then water comes out of Doraemon's pocket and suddenly a time portal is opened and his pocket is lost. He shows them his mega creation a sea monster.
This time our friends embark on a huge and unique boat in order to learn about the mysteries of the sea and look for treasures. Will they be able to overcome the dangers they will encounter? While walking they come across fruits which attack them. They get frightened seeing the god of sea but it was a image. The captain announces that they will go next morning. Then doraemon takes out anywhere door then Nobita tells he wants to feel the real thrill. They cross a bridge Doraemon remembers it will fall and they fall in a river and some bad guys attack them. When they regain consciousness they are in the ship and when they see outside a cannon hits them.