All Alone in the City of the Future

Nobita wants to invite everyone to go swimming, but Shizuka, Suneo, and even Gian are all planning a vacation. Nobita decides to ask Doraemon for help, but Doraemon says, "There's an important matter that requires me to go back to the 22nd century," and jumps into the "Time Machine". After thinking for a moment, Nobita decides to also travel to the 22nd century in the "Time Machine", boasting, "Only I can travel to the future!" When Nobita arrives in the 22nd century, he finds himself atop an unshielded tower, terrified. Just then, a spaceship passes by, and Nobita tries to attract its attention but fails, causing him to fall. Fortunately, there are anti-gravity facility on the ground, allowing Nobita to "Softly land." Nobita, finding the street deserts, tries to ask for direction at a shop that claims to be an "Automatic Clothing Vending Machine." The shop rips off his clothes, creates new ones using clothing gas, and doesn't charge him extra. Later, Nobita eats at a restaurant and wonders why the city is deserted. He then sees floating objects in the Sky Park and goes to investigate, discovering they are aggressive aliens. Nobita believes this "Alien Invasion" is the reason Doraemon wants to return to the 22nd century and decides to go home to find a way. On the way, he is pointed at by a gun. The gunman is Sewashi. Nobita asks Sewashi if 22nd-century Tokyo has been invaded, and Sewashi says yes, adding that the whole world is under attack. Just as Nobita laments how easily humanity could perish, Sewashi gives him a gun, urging him to fight the enemy. Nobita's marksmanship is impressive, impressing Sewashi. Suddenly, a large UFO appears and knocks them both unconscious. A child resembling Gian (named "Gambo") wakes Sewashi; it turns out Gambo has gone on a trip to the moon. Afterwards, a child resembling Shizuka and a child resembling Suneo appears: the girl resembling Shizuka went to Mars, while the boy resembling Suneo orbited the solar system. Sewashi takes Nobita away, but Gambo reveals that Sewashi is playing a 3D "Intruders" game. Nobita then realized that Sewashi has only been playing alone. Sewashi scolds Nobita for being "useless," saying that his descendant won't be able to go anywhere during summer vacation. Back home, Sewashi prepares drink and pastry to welcome Nobita, while Sewashi tells Nobita that the atomic furnace inside Doraemon has malfunctioned, so it went to the factory for repair. After Doraemon finishes repairing it, he returns to Sewashi's house, and together with Nobita, they travel back to the 20th century in the "Time Machine". Since the others haven't returned from their vacation yet, Nobita asks Doraemon to borrow another 3D "Intruders" game to play in the backyard, startling his mother who happens to be passing by.