Doraemon Movie 39: Nobita no Getsumen Tansaki

Nobita insists that strange activity observed on the Moon must be proof of moon rabbits, only to be laughed at by his classmates. Doraemon helps him turn the idea into something tangible by using a gadget that creates a habitable realm on the lunar surface, where Nobita and his friends can shape their own community of Moonbits.

Soon afterward, a mysterious transfer student named Luca appears, and Nobita recognizes him as a boy he previously glimpsed under strange circumstances. Luca's connection to the Moon reveals that the fantasy Nobita wanted to believe in is tied to a real people and a danger reaching far beyond Earth, drawing the friends into an expedition where imagination and reality become difficult to separate.