Nobita Nobi, weary of nagging parents and cramped Tokyo living, decides to run away from home. Joined by his loyal friends Gian, Suneo, Shizuka, and the robotic cat Doraemon, who also feel smothered by domestic life, Nobita proposes they travel back in time to pre-historic Japan, seventy thousand years ago, to establish a secret, uninhabited utopia where they can live completely free from adult authority.Equipped with futuristic tools and genetically modified pets—a pegasus named Pegasus, a griffin named Grif, and a dragon named Dra—the kids build a magnificent prehistoric sanctuary. However, their idyllic vacation is abruptly shattered when they encounter Kukuru, a primitive boy from the Light Clan whose village was brutally attacked and enslaved by the time-traveling villain Gigazombie and his ruthless Dark Tribe. Motivated by a strong sense of justice and newfound maturity, Nobita and his friends vow to rescue Kukuru’s captured family and stop Gigazombie’s tyrannical conquest.The group ventures deep into
the treacherous frozen tundras of northern Japan to infiltrate the Dark Tribe’s fortress. Tensions rise as the children face life-threatening perils, forcing them to rely on teamwork, courage, and Doraemon’s gadgets. Nobita, typically timid and clumsy, undergoes a profound
transformation, stepping up as a fierce protector of Kukuru and his people. During a chaotic, high-stakes battle, Gigazombie deploys advanced futuristic weaponry to crush the resistance. Despite being outmatched, the kids utilize their unique bond with their prehistoric pets and environmental tactics to dismantle the villain's time-distortion machinery.Gigazombie is ultimately defeated and apprehended by the Time Patrol, who arrive just in time to restore historical order. With peace successfully restored to the primitive world, Nobita and his friends share an emotional farewell with Kukuru and their beloved animal companions, knowing they must leave the past undisturbed. Returning to the present day, Nobita steps back into his ordinary life, but he is forever changed. He carries the quiet confidence and resilience forged in the ancient wilderness, finally appreciating his home and family with a newfound, mature perspective on freedom and responsibility.