The peaceful routine of Nobita and his friends is upended when Suneo and Gian force Nobita to help them shoot a sci-fi independent film using special miniature sets. Desperate to contribute something impressive, Nobita enlists Doraemon’s futuristic gadgets to build his own authentic spaceship. While exploring the forest, Nobita and Doraemon stumble upon a tiny, palm-sized humanoid alien named Papi who has crash-landed on Earth.Papi is revealed to be the youthful president of the distant planet Pirika. He fled his homeworld after a ruthless
military dictatorship, led by the tyrannical General Gilmore, launched a violent coup d'état to seize control. Gilmore’s formidable armed forces, utilizing advanced tracking technology and massive battleship armadas, relentlessly pursue Papi across the galaxy. Unwilling to endanger his new Earthling friends, Papi attempts to leave in secret. However, the merciless military
intelligence agency tracks him down. Giant, robotic spy drones materialize over the city, and enemy forces kidnap Shizuka as leverage to force Papi’s surrender, raising the emotional stakes for the entire group.Determined to rescue Shizuka and liberate Pirika, Doraemon, Nobita, Gian, and Suneo utilize a shrinking gadget to reduce themselves to Papi’s size. Aboard their high-tech starfighter, they journey across the stars to Pirika. Upon arrival, they infiltrate the heavily fortified capital and organize an underground resistance network alongside local freedom fighters.However, betrayal strikes from within, and Papi is captured by Gilmore’s elite guards. Facing public execution to crush the spirit of the rebellion, Papi refuses to submit. Just as despair sets in, Doraemon and Nobita execute a daring, multi-layered rescue plan. Leveraging their vast arsenal of secret gadgets—ranging from the Anywhere Door to the Time Cloth—they turn the tide of battle. Gian and Suneo conquer their personal fears, displaying immense courage by piloting heavy armor against the dictator’s mechanized legions.A massive, high-stakes interstellar battle ensues in the skies above Pirika’s capital. The friendship and unwavering bravery of the Earth kids inspire the oppressed citizens of Pirika to rise up en masse against their oppressors. General Gilmore’s forces are systematically overwhelmed and dismantled by the combined might of the awakened populace and Doraemon's futuristic technology. With the dictatorship officially overthrown, peace and democracy are restored to the planet. Papi is reinstated as rightful president, deeply indebted to his Earthling saviors. Nobita, Doraemon, and their friends bid a bittersweet farewell to Papi and the alien freedom fighters, returning to their normal lives in Tokyo with hearts full of unforgettable memories and a renewed bond of unbreakable friendship.