Shin-chan as a spy is the perfect excuse to break every rule the TV show follows without apologizing. The film leans hard into absurdist action parody instead of slice-of-life chaos, which means the humor gets sharper and meaner. You get legitimate spy thriller beats undercut by a five-year-old doing something unforgivable at the exact moment the plot demands competence. The stakes feel real enough that when Shin-chan inevitably torpedoes them, it lands harder than it has any right to. This is comedy that trusts you to know the character well enough that watching him sabotage everything becomes the entire joke.

Shinnosuke is living an ordinary life when a mysterious spy girl, Lemon Sunomono, suddenly appears before him and introduces herself as an emissary of Action Kamen. Her parents trained her as a spy in the Sukashipestan Republic, and she works for the Queens. With Lemon guiding him, Shinnosuke decides to become a spy who fights for justice and goes through spy training. On Action Kamen's instructions, the two take on a mission to sneak into a laboratory in the Hedelna Kingdom and retrieve a capsule from an evil professor. Along the way, Lemon learns what the Queens are really after, and she and Shinnosuke fight to foil their plot. The comic spy action includes fart gags, along with the story of a girl who had obeyed her parents and comes to think for herself.