The ninth installment of the Crayon Shin-chan films.
When a new 20th century themed open park opens in Kasukabe, it quickly wins over the hearts and minds of the nostalgic adult population. It becomes clear to Shin-chan and his friends that the museum is affecting their parents and the other adults who visit it.
When their parents end up losing their memories and return to the comfort and nostalgia of the 20th century, it’s up to Shin-chan and his friends to unravel this heinous plot and return their parents to the 21st century before the whole world follows them into the past!
This film contains examples of:
- Armor-Piercing Response: A tired Shinnosuke gives one to Chako when she doesn't comprehend why he fought for his future before collapsing.Chako: Why? Tell me why?! The 21th century is an aberration!
Shinnosuke: Because... I want to be with dad, mom, hima and shiro ... despiting fighting sometimes I still want to be with them... and because... I want to grow up ... I want to be an adult and have a lot of relationships with cute girls like you, that's why!. - Berserk Button: Ken doesn't take it lightly when someone messes with his beloved Toyota 2000GT.
- Beyond the Impossible: At first, when the Nohara adults find about the nostalgia essence after being de-brainwashed, they dismiss it as nonsense until Ken reminds them the same essence made them behave like kids again.
- Bungled Suicide: Ken and Chako almost jump into the abysm when their plans are foiled and admit defeat, only to be interrupted by both Shinnosuke and a nearby bird who thought they were a menace to its family.
- Crapsack World: Kasukabe without adults quickly turns into this, as children scarily try to survive in confusion over the sudden disappearance of their parents.
- Endless Daytime: One of the park's main locations is a small town where it's always afternoon.
- Evil Reactionary: The 'Tomorrow Once More' organisation is built upon the idea of keeping every Japanese citizen in their idealized version of the 20th century.
- From Bad to Worse: The world without adults becomes worse when the electricity goes out.
- Hypnosis-Proof Dogs: Shiro doesn't seem affected by the nostalgic essence in the slightest.
- Immune to Mind Control: All the kids in Kasukabe are immune to the nostalgic essence, but is implied by the park members that they will quarantine them in order to adjust them to live in the 20th century.
- Kids Are Cruel: Some kids who raided a store deny food to the Kasukabe Defense Force and other younger kids who were trying to survive. In return, they unsuccessfully try to sneak and steal some from them.
- Kids Driving Cars: To escape the adults hunting them, Shinnosuke and his friends sneak into the kindergarten neko-bus and drive it while taking turns.
- Lured into a Trap: After one day passes without adults, the park members arrive and assure them that if they go with them they will meet their parents again or else they will never see them again, not knowing the park members truly want to brainwash them. Not every kid falls under their trap as some kids including Shin and co who find their act suspicious, resulting in the adults being forced to hunt them the next day early in the morning.
- Manly Tears: Hiroshi shreds some of these when he regains his memories and hears his son ask if he still remembers him.
- Mass Hypnosis: The managers of the park of the 20th-century attempt to do this worldwide to return everyone into their idealized version of the former century.
- Nice Job Breaking It, Hero:
- The brainwashed parents ate all the food in the houses before leaving to the park, forcing their kids later to try to get food outside in any way possible.
- When the Kasukabe Defense Force sneaks into the store to get some food for the day, he tries to get some chocobi from a taller section, resulting in them being spotted by the bigger meaner kids who refused to share with them earlier and losing almost all of the food they gathered due to fleeing suddenly.
- Shinnosuke sets the clock to leave the city before the adults arrive to capture them too late.
- Nice Job Fixing It, Villain: The cameras around the 20th-century tower live-record the Nohara's fight for the future, making the citizens lose their nostalgic essence as they decide to root for the family.
- Nostalgia Filter: The entire park is built around this ideology towards the 20th century, and their creators manage to weaponize it with an essence that hypnotizes adults into behaving and turning into children.
- Only Sane Man: Razaya Dan, the TV news reporter is one of the only few adults who are acting sane, informing the kids about the sudden massive disappearance of adults in Japan before the park of the 20th century takes over his signal to showcase old programs from the old century.
- Out-of-Character Alert: Shinnosuke and all of his friends notice something is really wrong when their parents become obsessed with their nostalgia and start acting like children.
- Pleasure Island: The park of the 20th century starts out as a harmless park where adults could have fun by playing the games they used to play, visit the 70's expo, or becoming their childhood hero, but as time progress, the adults visiting it get intoxicated by their nostalgia and began acting like spoiled children, abandoning their adult responsibilities and moving on to the park to live there permanently.
- The Power of the Sun: One of Hiroshi's childhood heroes which he recreates in the museum, has the power to charge his energy with the expo solar tower.
- Shoo Out the Clowns: Due to being caught sneaking into the park, Shin's friends disappear from the plot and don't appear again until the ending, where every citizen in Kasukabe is returning home.
- Shout-Out: Both brainwashed Misae and Hiroshi do the Sheeeh pose to mock their son before leaving in the truck among other adults to the park.
- Silence Is Golden: The entire sequence of Hiroshi remembering his entire life is featured without any dialogue at all.
- Smelly Feet Gag: Hiroshi's feet odor is the only way for both Hiroshi and Misae to regain themselves and fight against their nostalgia.
- We Interrupt This Program: While watching tv, one of the few sane adults remaining informs the kids about the sudden massive disappearance Shin-chan saw earlier, which is interrupted by an old wrestling match when the reporter was about to give the details of the case.
