Nobita, who visited the dinosaur exhibition with his friends, and in a fossil excavation experience vows to his friends that he will discover a dinosaur and dares to eat peanuts with his eyes if he does not fulfill the dare. As he left the excavation experience he trips over a rock, and suspects he has found a fossil egg. He goes home and convinces Doraemon to use “time wrapping cloth” on the fossil egg and twin feathered dinosaurs emerged. Doraemon found that they are a new species of dinosaur not listed in the “Complete Encyclopedia of Space”. Nobita named the twin dinosaurs Kyu and Myu, and under the advice of Dr. Dinosaur learned how to take care of them. The two fast-growing animals gradually showed a difference. While Myu has learned to fly, Kyu has not and was smaller in size than Myu. As Kyu and Myu grew bigger, Nobita’s room was not enough so they used the “Breeding diorama set” to allow Kyu and Myu more freedom. The day where Nobita fulfills his dare came, and as his friends arrived they discovered that Nobita has indeed found a dinosaur. At this point Kyu and Myu made a lot of commotion leading to Nobita’s mom to come upstairs. They tried to hide Kyu and Myu by using the “spatial movement crayon”, however, the townspeople saw Kyu and Myu. They realized Kyu and Myu reached the limit of growth, and should return to their time. Nobita had trouble accepting this, but decided it might be the best option. The next morning, the five of them climbed into the “time machine”.
In “Time Furoshiki” Doraemon’s party goes back to the late Cretaceous, calculated from the time of the fossil egg. However, they discovered they were in the Jurassic period instead. As they are rushing to return to the “time machine” Nobita tripped and lost the “Breeding diorama set” in a swamp. The scene switches to a room where the actions of Nobita and his friends are secretly monitored by Jill, who is in the form of a white monkey, as he answers a call by a mysterious woman names Natalie. Unaware that they are being monitored, the group searches for Kyu and Myu’s comrades, and finally reaches the sea where along the way dinosaurs like Cole, a Tarbosaurus who originally attacked them, and Top, a Sinoceratops, joined during the voyage as both were tamed by ” Tomodachi Chocolate”. When Gian and Suneo went ahead to find more clues about Kyu and Myu’s comrades, they are captured by Jill, and Doraemon and others are in danger of being attacked by a large pterosaur. Nobita and Kyu fall into the sea, but are helped by a plesiosaur that is suspiously similar to Piisuke who took them to a mysterious island where they reunite with Doraemon, Shizuka and Myu. This is an island inhabited by dinosaurs that look like them same species as Kyu and Myu. Nobita tries to get the two back to their group, but Kyu is scratched and refused by the group because they believe Kyu is different. Is it because, unlike other new dinosaurs, Kyu cannot fly and its tail is shorter? Trembling with grief and sorrow, Nobita declares that Kyu can fly wonderfully by itself.
Meanwhile, Jill and Natalie, who was on their way to the island on a submarine, said a deep impact was immediate. Gian and Suneo, who are watching them escape from the cage, look at the map and see the truth of the mysterious island. At the time, Nobita and Kyu, who had just started flying training, had a misunderstanding and the training was disrupted. Nobita looked down, silently encouraged, and when he searched for a note with the “question stick” there was a figure of a mark who was constantly practicing alone. He started training to touch Nobita because he was able to do the reverse climb. At that moment, a huge object shining in the sky falls.
Gian and Suneo also ran further in, when they were all together, Doraemon tells everyone that this was the time period that caused the Cretaceous extinction when a meteorite struck Mexico on the Yucatán Peninsula 66 million years ago. Nobita tries to use an “opposite direction” to turn the meteorite into space, but the “Time Patrol” appears and Natalie stops the party’s activities. Jill reveals that they were looking at this era as a one-time patrol, and insists that history cannot be changed even if he thinks about dinosaurs and is close to Nobita’s heart. Nonetheless, Nobita, who tried to use the “opposite direction” machine, was stopped and detained by the Time Patrol. Kyu and Myu rush to protect Nobita, and Doraemon and others who tried to protect him are also detained. However, when Jill holds a “check card” on Nobita and Kyu, the card emits light. Jill and his time patrol decide not to interfere in their activities.
As the team fights to help Kyu, Myu and the other dinosaurs, information provided by Gian and Suneo revealed that the island was actually the “Breeding diorama set”, dropped by Nobita during their time in the Jurassic period, and became active and larger as time passed. They decided to move the dinosaurs outside of the island onto the island with the “Space Movement Crayon” and launch a rescue operation to protect them from the hot air of the meteorite collision with the Diorama’s “weather control function”. As the meteorites approach, the pterosaur strikes Nobita and Doraemon as they are drawing the circle. As Nobita hangs onto the pterosaur Kyu is attempting to fly to reach and rescue Nobita, but Kyu is struggling immensely. As Kyu tries and tries, Kyu is slowly evolving as he starts to flaps his wings and after multiple tries Kyu was able to fly. Kyu rescues Nobita right after Nobita lets go due to exhaustion. From gliding to flapping, from dinosaurs to birds, Jill and his colleagues marvel at the birth of history as the first step to evolution. The dinosaurs were rescued and settled on the island, and Nobita and his friends said goodbye to Kyu and Myu. Jill exaggerates the caring heart like the dinosaur that formed the wings and the man who created so many emotions in the appearance of such a party. After returning to the current era, Nobita challenges himself to a bar reversal that he could not do, and eventually succeeds.