Throughout the film, Nobita is obsessed with proving himself. He wants to be a hero like the pirates in his books. Why? Because his real father (Nobisuke) is a salaryman who falls asleep at the dinner table. Nobita fears he will grow up to be mediocre.
Inside, not treasure, but a server rack—still powered by a solar battery. On its sole screen: a live chat interface. A single message blinked: