The Great Detective's Notebook in Kasukabe

“Action Kamen! Action Beam! BIBIBI, ”

When Nohara Shinnosuke digs for “treasure” in the backyard of Futaba Kindergarten, he never imagines that his rusty little trowel will unearth the “key” that changes two worlds: a silver pocket watch engraved with “APTX.”

At the same moment, in the Tokyo Metropolitan Police Department, Edogawa Conan, the “Heisei Era’s Sherlock Holmes” (Kudo Shinichi), stares at a sudden burst of static on his computer screen. On the TV, a red-shorted kid with a bowl-cut hairstyle stands with his hands on his hips, shouting, “Mom, I found an alien toy!”

The barrier between parallel worlds shatters because of a pocket watch.

Kasukabe and Tokyo, two places that should never have intersected, begin to overlap. The cherry blossom necklace Shin-chan finds becomes key evidence in a string of thefts in Tokyo. A member of the Black Organization whom Conan is tracking disguises himself as a new kindergarten teacher and infiltrates Shin-chan’s life. A black FBI car flashes past the window while Misae cooks miso soup. An anonymous warning suddenly pops up in Hiroshi’s office worker overtime group chat: “Beware the trap at the Kasukabe shopping mall sale”...

One is a five-year-old troublemaker who can turn “Butt Alien” into a requiem. The other is a famous detective solving cases in an elementary schooler’s body with an adult’s soul. One exposes a disguise through “Kazama’s new schoolbag being painted to look like an elephant’s butt,” while the other pins down the culprit by reconstructing the timeline. When Shin-chan’s “childish intuition” meets Conan’s “precise deduction,” this “adorable age-gap duo” gets swept into a crisis even stranger than the Black Organization, beneath the sunshine of Kasukabe.