Rupert and his friends have a new classmate — Ottoline Otter. She's rich, friendly, fearless, and loves exploration and mystery as much as Rupert does. Her family has moved into the remaining spooky, abandoned, "haunted" mansion in town, Nutwood Manor, which their ancestors were forced to give up after the last Earl stole the gold the King entrusted to him and disappeared. When a "ghost" crashes a party she's throwing, Ottoline's and Rupert's investigation takes them into the manor's labyrinth of secret passages and tunnels, which hold no shortage of secrets... and they're not the only ones interested in them...
First appearance of the troublemaking Fox twins.
This episode provides examples of:
- All Girls Like Ponies: Ottoline has her own horse, Blaze, who helps the kids out in the climax.
- Arc Words: "To few is honour greater than gold."
- Bad Boss: Dr. McCormick treats Fraser like crap. It's no wonder his lackey snaps before the adventure is over.
- Bedsheet Ghosts: Freddie and Ferdie try to pull this prank at Ottoline's party. It's as pathetic as it sounds.
- Chekhov's Gun: During their treasure hunt, Rupert and Ottoline find an old trunk they hope contains the treasure but is full of nothing but centuries-old clothing. It comes in handy later when Rupert attempts a Scarecrow Solution.
- Concealing Canvas: At least one painting in Nutwood Manor is secretly the trigger to open a secret passageway.
- Decoy Sidekick: The episode begins looking like it will be another Rupert/Bill adventure, but Rupert spends the majority of the plot with just Ottoline.
- Don't Be Ridiculous: When their toy plane accidentally lands in Nutwood Manor's courtyard, Rupert thinks Bill is being silly for being afraid of the ghosts... because ghosts don't come out in the daytime.
- Dramatic Irony: The audience meets the duo behind the ghost pranks before the heroes do.
- Elegant Classical Musician: Ottoline is practically an expert piano player, being able to flawlessly play a classic song by heart after the Fox brothers sabotage the teacher's sheet music.
- Establishing Character Moment: Ottoline is told about her haunted house in her very first scene in the series. Dr. Chimp is upset her classmates are "scaring" her, but she simply assures everyone she has nothing to worry about since any ghosts in her ancestral home would be her family.
- Everyone Calls Him "Barkeep": The Otter who hid the King's gold is only referred to as the "Earl," despite the fact that there would have been multiple Earls before him.
- Evil vs. Evil: Fraser eventually gets sick of taking orders from Dr. McCormick and putting up with his constant insults, but it doesn't prompt him to make a Heel–Face Turn, just to fight with him over who's in charge.
- Failed a Spot Check: Dr. McCormick hit a dead end when following the Earl's trail of clues because he apparently never thought to check the back of the last painting he found.
- Ghostly Wail: All 4 people impersonating ghosts do this.
- Hypercompetent Sidekick: Fraser turns out to have far more common sense than Dr. McCormick, at least enough to realize their "Scooby-Doo" Hoax isn't going to work forever and that the best way to find the treasure is to let Rupert and Ottoline do the hunting.
- I Don't Pay You to Think:Fraser: I heard the girl say the Earl ran off the the gold. I think we...Dr. McCormick: NO! You don't think! How many times do I have to tell you?!
- It Belongs in a Museum: Ottoline's parents turn the King's treasure over to the Royal Museum (appropriate, given that the Earl always intended to keep it safe for the King, and it never belonged to the Otter family).
- Linked List Clue Methodology: The last Earl left clues to where he hid the King's treasure in this style.
- No Name Given: The last Earl of Nutwood Manor is never named.
- Nobody Calls Me "Chicken"!: Bill is ready to pass on Ottoline's party at Nutwood Manor until she assures him "ghosts aren't invited," so he has to go to prove he couldn't care less about ghosts.
- Portrait Painting Peephole: Nutwood Manor is full of these.
- Powder Gag: Inverted. Rupert covers himself in white powder so he can pretend to be the ghost of the Earl and scare the villains into compliance. It seems he's succeding when one of the latter sneezes so explosively that Ruper's flour disguise dispels in a white cloud.
- Real After All: The actual ghost of the Earl suddenly appears in the episode's last scene.
- Remember the New Guy?: Ottoline is just now moving to Nutwood, but the Fox twins have apparently just never been seen until now.
- Scarecrow Solution: Using a bag of flour, some old clothes, and a white horse, Rupert gives a convincing enough performance as the ghost of the Earl to make the villains hand over the treasure map. (Unfortunately, the tendency of one of them to sneeze at the slightest exposure to flour gives him away.)
- "Scooby-Doo" Hoax: The "ghosts" of Nutwood Manor are a discredited university professor and his hired muscle, scaring people away so they're free to search for the King's missing treasure.
- Traveling at the Speed of Plot: Night falls at some point while Rupert and Ottoline are following the clues. The sun rises shortly after they find the Roman ruins... so did they follow Dr. McCormick and Fraser around the marsh for 8 hours...?
