Papi, the central character, originates from planet Pirika where he serves as president despite his youth. A coup led by General Gilmore forces him to flee in a small rocket. His sister Piina ensures his escape by staying behind, leading to her capture by Gilmore's PCIA intelligence agency, commanded by Colonel Dracoruru. Papi crash-lands on Earth, where Nobita discovers his miniature rocket. Initially appearing palm-sized, Papi reveals his status as a political refugee to Nobita, Doraemon, and their friends. His small stature causes confusion until the group uses Doraemon's "Small Light" gadget to shrink themselves for direct interaction. During this time, Papi notices a resemblance between Shizuka and his sister Piina, intensifying his concern for Piina's safety. Facing relentless pursuit by the PCIA, Papi demonstrates personal responsibility. When Shizuka is captured as leverage, he voluntarily surrenders to secure her release. Later, learning Piina remains captive on Pirika, he resolves to return home and confront the dictatorship. Back on Pirika, Papi aligns with the Freedom Alliance resistance. He strategically attends Gilmore's coronation ceremony, seizing the live broadcast to deliver a speech directly to the populace. His words condemn Gilmore's tyranny and express faith in the people's desire for freedom, inspired by lessons of courage and solidarity learned from Nobita's group. The speech successfully mobilizes widespread public defiance. During the ensuing conflict, Papi faces execution alongside his Earth companions. Their survival hinges on the timely expiration of the "Small Light" effect, which restores Doraemon, Nobita, and Gian to normal size, disrupting the PCIA. Following Gilmore's defeat and surrender to the revolting citizens, Papi reunites with Piina. Their emotional exchange underscores their familial bond, with Piina acknowledging Papi's growth and leadership, allowing him to release pent-up emotions. Papi ultimately resumes his leadership role on Pirika, promising ongoing friendship with the Earth group before their departure. Papi's pet dog, Rokoroko, accompanies him throughout. Rokoroko provides assistance during rescue attempts and deliberately delays the execution with a lengthy speech, aiding the group's escape.