While at the Danville Swap Meet, Lawrence tells Phineas and Ferb about the 1807 Dorcham and Wesley Boot Scraper; only one of them was made and it was lost to the mists of time. Phineas and Ferb decide to take Lawrence on a quest to find the boot scraper. Meanwhile, Candace finds a rare Ducky Momo pull toy that the dealer isn't willing to sell; she then has to go through a Chain of Deals with other dealers in order to get the pull toy. At the same time, Dr. Doofenshmirtz has made a propaganda film and intends to enter it into the Danville Young Filmmakers Festival. The problem is that the films must be made by entrants who are younger than 15 years old, so Dr. Doofenshmirtz invents the De-Age-Inator, a device that will transform him into a 14-year-old boy.
Tropes
- All for Nothing: Candace completes her Chain of Deals and is about to get her Ducky Momo collectible in exchange for the baby rattle, but then the De-Age-inator hits the rattle, restoring it to pristine condition, the dealer notices and cancels the trade, and boy is Candace upset.
- Big "WHY?!": Candace screams this, combined with Skyward Scream, when the antique baby rattle is hit by the De-Age-inator and returned to pristine condition, resulting in the trade being cancelled.
- Booby Trap: The museum that Phineas, Ferb and Lawrence enter is filled with these.
- Chain of Deals: Candace's part of the episode has her pulled in to one of these to get a rare Ducky Momo collectible. She is able to make these trades when the last booth only wants one dollar.
- Continuity Nod: Among the characters in flying saucers during the ending are Conk the Caveman from "Boyfriend from 27,000 BC", Garbog from "Invasion of the Ferb Snatchers", the watermelon from "Attack of the 50 Foot Sister", and Jeremy-Tree from "Wizard of Odd".
- Chekhov's Gun: The Danville's Young Film Makers festival that Doof wanted to win turns out to be what Phineas and Ferb were doing in their plotline, as the adventure they were seemingly having was actually their film.
- Continuity Nod: One of the items at the swap meet is a mudflap with an image of Perry as a pirate saying "BACK OFF!", in a parody of the Yosemite Sam mudflaps from "Suddenly Suzy".
- "Do It Yourself" Theme Tune: Major Monogram does not know what Doof is up to because he was busy setting ringtones for his contacts, including Agent P and Carl with their respective Leitmotif. He wants to make a ringtone for himself, but he does not have his own theme song. During the credits, he feebly attempts to write one.
- Don't Explain the Joke: Perry gets trapped in film celluloid, and Doof says, "Well, as they say in the film business, it's a 'wrap'! Get it? Because you're 'wrapped'! In 'film'!"
- Fountain of Youth: The De-Age-inator causes anyone or anything to become younger.
- Gainax Ending: It turns out that Worthington DuBois can turn into a giant ghost and has enemies from outer space. And Phineas and Ferb battle him in flying saucers with the help of one-shot characters from previous episodes. But as it turns out, this was all just a part of Phineas and Ferb's entry into the film festival.
- Leaning on the Fourth Wall: When Candace sees the rare Ducky Momo collectible, she cheers, "Heavenly light, angel chorus!"
- Letting the Air out of the Band: When an exhausted Candace finally reaches the last dealer she needs to talk to.
- Literal Metaphor: Lawrence laughs at his own joke that you could find anything "under the sun" at the Danville Swap Meet, because it's held outdoors, which is literally under the sun.
- Needle in a Stack of Needles: In a Shout-Out to Indiana Jones and the Last Crusade, the Dorcham and Wesley Boot Scraper is hidden amongst several other boot scrapers with different designs. Lawrence must choose the correct boot scraper in order to avoid setting off an unwanted booby trap. His rival rushes in and picks the wrong one, triggering the trap; after that, Lawrence just grabs as many boot scrapers as he can and bolts, reasoning that it won't matter because the trap was already triggered.
- No Ending: Doof is not returned back to his normal age and ends up having to ask for a ride home, since he's now too young to drive himself home.
- Proscenium Reveal: It turns out the whole Phineas and Ferb part of the episode was a film made by them.
- "Shaggy Dog" Story: Candace's part of the story ends with her failing to get the Ducky Momo figure after the baby rattle is hit with the De-Age-inator and the dealer cancels the trade because of this.
- Shout-Out: To Indiana Jones and the Last Crusade, when Lawerence and the boys find all of the different boot scrapers is a direct reference to where Indiana Jones found the holy grail hidden among dozens of other cups. Lawrence's rival triggering a booby trap by choosing the wrong boot scraper even has Phineas repeat the crusader knight's line of "He chose poorly".
- Special Guest: Tim Curry as Worthington Dubois.
- That Poor Cat: When Worthington Dubois pushes Lawrence aside, this is heard.
- Totem Pole Trench: Worthington Dubois is revealed to actually be Baljeet and Buford sitting on top of each other.
- Whole-Plot Reference: To the Indiana Jones and National Treasure movies. The title is modeled after National Treasure 2: Book of Secrets while the hidden temple, with all of its booby traps is modeled after the many tombs and ruins visited by the esteemed Dr. Jones.
- Yank the Dog's Chain: Candace has completed the long Chain of Deals and is ready to get the rare Ducky Momo collectible... only to be denied the trade last-minute when the baby rattle's patina is cleaned off by the De-Age-inator.
