While visiting their family in England, Phineas and Ferb decide to build an invention in London. After staying up all night reading a collection of Sherlock Holmes novels, Candace (with Stacy by her side) decides to use Holmes' method of deduction to figure out what they're building (and where). Meanwhile, Perry, with the help of Agent Double 0-0 from Her Majesty's Secret Service, is sent to foil Dr. Doofenshmirtz' plan to use rockets to steal Big Ben and fly it to the Tri-State Area.
Tropes
- All Women Love Shoes: While Candace tries to find out what her brothers are up to, Stacy instead gets repeatedly pulled out of the action because she's distracted by shoes and other fashion items.
- Arson, Murder, and Jaywalking: Double 0-0's car has radar, subatomic sonar, a nuclear particle response system, and an MP-3 player.
- Artistic License – Engineering: In this episode, the London Eye stops to let its riders off; unlike the real London Eye which never stops rotating unless it is in need of repairs.
- Attention Deficit... Ooh, Shiny!: Stacy keeps getting distracted by shopping throughout Candace's search for clues.
- Bait-and-Switch: "Hey, where's Perry? Oh, there he is!"
- Barely Missed Cushion: Doofenshmirtz attempts to use the boys' waterslide to escape Big Ben, but since he already launched the tower, he's flung a bit too high and instead of landing in the water, he crashes into the pavement right next to it.
- Brick Joke: During The Stinger, Agent Double 0-0 attempts to swing off the pendulum of Big Ben, then makes it onto the clock face, then looks at his wristwatch and says he needs a bigger watch.
- Complexity Addiction: Doofenshmirtz wants to steal Big Ben and fly it to the Tri-State Area to use as his personal clock... because his wristwatch is too small for him to read. He thinks buying a bigger clock would be too much work.
- Continuity Nod: Monogram mentions Agent P's last mission in London.
- Creator's Culture Carryover:
- When Stacy and Candace are in the back alley behind the auto parts store, there's a sign that says "Free Tires". In the UK, the word "tire" is spelled "tyre", so the sign should say "Free Tyres" instead.
- Also, auto parts stores are referred to as "Car Spares" or "Motor Spares" in British English.
- Candace goes to 1600 Water Street under the assumption Phineas and Ferb are having a big race there. London doesn't have a 1600 address, because the UK uses different road and house numbering systems than America's (The "A" system for roads, while house numbers rarely breach 1000).
- When Stacy and Candace are in the back alley behind the auto parts store, there's a sign that says "Free Tires". In the UK, the word "tire" is spelled "tyre", so the sign should say "Free Tyres" instead.
- Ejection Seat: Double 0-0's car has one; unusually, it's installed on the driver's seat of the car rather than the passenger seat. Agent P presses the button before Double 0-0 has a chance to explain what it is, throwing Double 0-0 out of the car. Double 0-0 is not amused.
- Haggis Is Horrible: Inverted. Not only do Grandpa Fletcher and Lawrence enjoy it, but there's an entire festival dedicated to haggis that they're attending.Lawrence: There's 29 individual flavors!
- I Heard That: Candace says to Stacy quietly, "Ah, yes, reading. That's what they did before they invented fun.", and Grandma Winnifred responds with this.
- I Work Alone: Perry seems to dislike working with Double 0-0 due to the latter's bragging of the gadgets he uses. Even after being told to work with Double 0-0, Perry finds Double 0-0's methods of stopping villains to be quite ineffective in nature. For instance, when Double 0-0 attempts to cut himself out from Doof's trap with his laser watch, Perry flatly throws a brick at Doof's remote to free himself and Double 0-0, who gives credit to his watch, much to Perry's annoyance. He's even amused when he activates the ejector seat on Double 0-0's car, much to Double 0-0's frustration.
- Laborious Laziness: When his declining eyesight made his wristwatch harder to read, Doofenshmirtz decided to fly to England and steal Big Ben rather than go through the perceived hassle of driving to the store and choosing between dozens of watch styles.
- Mistaken Nationality: Initials generalizes both Monogram and Perry as American, even though Perry, being a platypus, originated from Australia.
- Model Planning: Doofenshmirtz made a scale model of both London and Danville to show Perry and Double 0-0 how he intends to fly Big Ben to the Tri-State Area (complete with a small, scale model version of Doofenshmirtz himself).
- No Celebrities Were Harmed: Inspector Initials is a parody of Dame Judi Dench's interpretation of M.
- Sherlock Homage: Candace and Stacy wear the classic Sherlock outfit and perform an investigation to find out what Phineas and Ferb are up to.
- Shout-Out: Agent Double 0-0's character contains a few inevitable shout-outs to James Bond; his name is an obvious parody of Bond's designation, 007, and his car is designed to resemble Bond's Aston Martin DB-5.
- Stating the Simple Solution: When Doofenshmirtz tells Perry and Double 0-0 about his plan to launch Big Ben and fly it to the Tri-State Area, Double 0-0 says, "You realize you could just buy a bigger watch? Or maybe a wall clock?"
- Theme Naming: The secret agent higher-ups Major Monogram and Inspector Initials. Not only do they share the alliterative naming scheme, but they are both named after glossary terms in language and typography.note
- Unintelligible Accent: The car parts salesman speaks with a thick Cockney accent that Stacy has to translate for Candace using a Cockney to English dictionary. While he does use some genuine cockney slang for the first half of their conversation, about half-way through he starts using several made-up Cockney-sounding words ("bic", "bushies", "bangers", "harrish"), likely to sound even more foreign and unintelligible.
- Vacation Episode: The second episode set in England.
- Weird Trade Union: Agent P is forced to work with Double 0-0 because the OWCA ran into some trouble with the British Spy Union after Agent P's last mission in England.
- Writing Indentation Clue: Candace uses this on a half-note left by Phineas and Ferb to figure out where they're going to be.
- Wrong Genre Savvy: After Agent P and Agent Double 0-0 are free, they have to follow Doof to catch him. There are the stairs that Doof already took. But rather than taking the stairs, Agent Double 0-0 goes up through the inner workings of Big Ben. However, Agent P takes the elevator to beat Double 0-0 to it. Double 0-0 eventually makes it to the top... in The Stinger, long after Doofenshmirtz has been foiled.
- The Wrong Way on the Escalator: During the song "Elementary", Candace and Stacy are going up an escalator while Phineas and Ferb are going down on the other side. They both immediately run back down the up escalator to catch them.
- You Have GOT to Be Kidding Me!: When Agent Double 0-0 learns of Doof's half-baked scheme, he asks Agent P if he is "on one of those hidden camera shows".
