Dr. Doofenshmirtz mentors a young up and coming evil scientist, unaware his student has sinister intentions. Luckily, Agent P. has backup in the form of Monty Monogram, his boss' son!
Meanwhile: Phineas and Ferb decide they can't wait until autumn to jump in a pile of leaves, and create a giant leaf pile to celebrate "S'Fall".
Tropes
- All Girls Want Bad Boys: Vanessa, which she blames on having an evil dad that she loves. At the end of the episode, she decides to drop it and give good guys, namely Monty, a try.
- Bait-and-Switch Sentiment:Major Monogram: Carl... Did I ever tell you you're like the son I never had?
Carl: [smiles] Really sir?!
Major Monogram: Yes, it's because you're so unlike the son that I did have and here he is, come on over here, Monty. - Breaking the Fourth Wall: Doof says that "Evil science is like undergoing deep Freudian analysis, with a theremin constantly playing in the background" as a synthesized theremin plays.
- Chekhov's Skill: Monty's acrobatics training as a child comes in handy when he throws up a rope swing and uses it to fight Rodrigo.
- Comically Missing the Point:
- When Phineas and the gang discuss summer coming to an end, Baljeet excitedly reveals his elation for the school year starting again, before realizing the others were sad about that fact.
- Candace spends most of the episode convinced the boys' project is merely hidden in the giant leaf pile, and not that the leaf pile itself is the project.
- Even Evil Has Standards: When Doof hears Rodrigo's plan to take over the world, which he sees as "left-boot-trap crazy".Vanessa: Oh, would you get off that? Making matching boots is normal. You with the one boot, that's what's crazy.
- Eviler than Thou: Rodrigo to Doof. He wants to destroy the Tri State Area, take over the world, and will kill Heinz and Perry to do it. He also upgrades Heinz's trap to one Perry cannot get out of without help.
- Fun with Acronyms: Monty is a recent graduate of HSWCA, the High School Without a Cool Acronym.
- Jaw Drop: Perry, when Vanessa starts to show a romantic interest in Monty.
- Not So Stoic: Agent P briefly smiles when he greets Monty. He also smiles when he sees Monty's fighting style.
- Offscreen Breakup: Vanessa breaks up with Johnny over the phone.
- Oh, Crap!: Perry's reaction both when Rodrigo reveals his real intentions and when he realizes Vanessa may like Monty.
- Record Needle Scratch: When Vanessa angrily rejects Rodrigo's proposal to "join [him]".
- Sequel Episode: Phineas and Ferb's "S'Fall" project is a sequel to "S'Winter".Phineas: Ferb, I know what we're gonna do today! Remember when we made S'Winter? Let's make S'Fall! Hey, where's S'Perry?
- Speaks Fluent Animal: Doof reveals to Rodrigo that he doesn't really understand what Perry says, but just pretends he is talking about movies he likes. However, Vanessa gathers Perry's reaction perfectly later.
- Special Guest: Seth Green makes his first appearance as Major Monogram's son, Monty, and Jorge Garcia (Hurley from Lost) appears as Rodrigo.
- That Poor Cat: One is heard when Doof throws his broken pointer stick offscreen.
- Too Dumb to Live:
- Rodrigo thinks that just because he had "a moment" with Vanessa, she'd betray her father for him. Vanessa angrily lampshades this to Perry.
- Vanessa herself, when she puts on her father's boot trap as a shoe while forgetting it's stuck to the floor, which forces her to sit out the climax.
- The Unreveal: Played for laughs, Buford claimed the gourd helmets he made for everyone capture their essence. When Isabella asks how hers does that, Phineas claims it's obvious and assumes she must be kidding.
- We Can Rule Together: Rodrigo asks Vanessa to betray her father so they can rule the world together. She flatly refuses.
