Helen is reading a book to Martha about a girl named Curious Crystal and and her dog Winky, who are trying to stop a robbery. Helen then wonders if someone in Wagstaff City has a big, dark secret and she dresses up as "Heroic Helen", bringing Martha as "Sidekick Sparky" to investigate. However, she finds nothing abnormal and gives up, while Martha leaves awkwardly after hearing someone "Psst" her from a bush.
At school, Mrs. Clusky notes that, oddly enough, all her students did badly on their math quiz, which is a practice test for another one the next week, except T.D., who got an A. Then, at the corner store, the girls discuss how strange this was. Carolina thinks this is unbelievable, and he must have cheated.
At the park, Helen spots T.D. being given an envelope by another boy and wonders if T.D. did cheat after all, the envelope contains the quiz answers, and this is the secret she's been looking for. She approaches him when the other boy leaves, but it turns out that the envelope only contains a comic book.
However, T.D. is then seen talking to Martha and Francois, saying that he thinks Helen "suspects something" since she was standing in a book watching him. Martha freaks out and suspects that Helen "knows", saying she can't "do this" anymore, but T.D. convinces her and Francois to with hot dogs. Then, it's revealed that T.D. is indeed cheating — he's having Francois (because he's the teacher's dog) give him the answers with hot dogs as payment, and Martha help.
The next day, Helen asks Martha if she wants to help her "patrol the neighbourhood for secrets", but she bails out, claiming to be going to the butcher's shop. Helen walks off in her Heroic Helen garb and bumps into T.D., who's just bought a bag of hot dogs. She asks if he's having a barbecue, and he awkwardly lies that they're for O.G. "for emergencies". She goes to the butcher's shop, where Carl reveals that Martha hasn't been to. Helen now suspects that Martha is in cahoots with T.D., but at the same time, she thinks it's odd that Martha would lie, especially to her.
Martha, meanwhile, is feeling very guilty for lying, but keeps going because of the hot dogs. She takes them to the park and eats them, but is caught by Helen. She asks Martha where she got the hot dog from, but she denies even having it. Helen asks why she wasn't at the butcher's shop, but Martha runs off, pretending that she's being called.
The next day after school, Helen follows T.D. She's surprised that all he's going is home, but then she sees Martha and Francois following him. She watches and sees that the dogs are helping T.D. cheat for the price of hot dogs, then Martha smells her. Helen busts the three and chases them, but they hide in a bush and get away.
However, a hole is ripped and the hot dogs fall out, and Helen follows the hot dogs. T.D., Francois, and Martha hide near the sports field, and Martha worries she'll have to run away. Helen shows up and berates the two for stealing quizzes, but Martha claims that Francois is only tutoring T.D. (with her translating) since Mrs. Clusky has taught him math. Helen wonders why T.D. was so secretive if he wasn't cheating, and he explains that he's just embarrassed that a dog is better at math than him, and he got the idea due to understanding math better when Martha tried to teach him that one time. He then gets full marks, and gives the dogs more hot dogs to say thank you.
This episode provides examples of
- Accessory-Wearing Cartoon Animal: Francois is seen napping in a sleep mask.
- Alliterative Title: Helen reads a book series called Curious Crystal.
- And I'm the Queen of Sheba: When Helen suggests that T.D. must have stayed up late studying, Carolina replies, "Yeah, sure, and while he was studying, maybe he had a midnight snack... from his steak tree!".
- And Your Reward Is Edible: T.D. thanks Francois for tutoring him and Martha for translating by giving them more sausages.
- Astonishingly Appropriate Interruption:
- Francois asks for more hot dogs, then T.D. holds up the bags and says, "They're right...", then Helen comes up and says, "Here, how could you do this?!".
- When T.D. is about to reveal what the prize is for the dogs, he says, "It's..." and then Martha yells, "Ample chicken sausages!".
- As You Know: Mrs. Clusky points out that she's sure her students all know what a quiz is, but she defines it anyway.
- Blatant Lies: When Helen asks Martha where she got the hot dog, Martha says there was no hot dog, even though Helen just saw her eat one.
- Buffy Speak: When Martha smells Helen, she says that it smells very "Heleny".
- Continuity Nod:
- Upon learning that T.D. got an A in math, Carolina says, "He said steak grows on trees!" (which was the plot of "T.D. and the Steak Tree") and then "He thinks dinosaurs play hockey!" (which he thought in "Dinosaurs in Trouble").
- T.D. remembers "when Martha taught class", which happened in "Martha Goes to School".
- Enfant Terrible: The main villain of Helen's book turns out to be a little boy. According to Martha, every Curious Crystal book involves a twist villain.
- Entertainment Below Their Age: This episode reveals that T.D., to his embarrassment, reads a comic series "for little kids" called The Love Bugs.
- Everybody Hates Mathematics: With the exception of T.D., Mrs. Clusky's entire class did badly on the test.
- Evil All Along: In Helen's book, Crystal's neighbour Bobby turns out to be the main villain Robbing Robin all along.
- Facepalm: Helen's imaginary double puts her hand on her forehead when she can't believe Helen fell for Martha's lie.
- Flashback: When T.D. explains how he flunked math, we see it happen.
- Food as Bribe: T.D. gets Martha and Francois to do his bidding by giving them hot dogs.
- Foreshadowing: The fact that Martha was helping T.D. to cheat is foreshadowed by her gulping and acting nervous when Helen suggests someone might be keeping a secret, and being "Psst"ed from a bush.
- Good with Numbers: Francois is revealed to be able to do math due to having learnt from Mrs. Clusky.
- Hesitation Equals Dishonesty: Whenever a character lies in this episode, they pause a lot.
- Hidden Depths: Francois is revealed to be Good with Numbers in this episode.
- Immediate Self-Contradiction:
- Martha says, "I can't do this! I can't!", but then when T.D. feeds her hot dogs, she says, "I can do this!".
- She later says, "I don't have to eat every hot dog right away, do I? ... I have to eat every hot dog right away!".
- I Need to Go Iron My Dog: Subverted. Martha's initial excuse for not investigating with Helen is that she needs to "go do a thing at the place", but then Helen says, "What place?", meaning Martha has to think up a better lie.
- Kid Detective: Ten-year-old Helen investigates T.D., who she suspects of cheating on a test.
- Lazily Gender-Flipped Name: Discussed when Martha worries that she'll have to run away, pretend to be a male dog, and change her name to Marty.
- Loud Gulp: Martha gulps when Helen wonders if someone in Wagstaff City has a big secret.
- Mad Doctor: Conversed by Martha, who notes that one villain in Curious Crystal was an ear doctor.
- Midnight Snack: Discussed when Carolina mentions T.D. having a midnight snack from his steak tree as part of an And I'm the Queen of Sheba response.
- Mondegreen Gag: In the flashback, T.D. is seen being so sleepy during math class that he mishears Mrs. Clusky's lesson as "Lollipop crocodile underpants. Skateboard cotton candy on teddy bear."
- My God, What Have I Done?: Martha feels very bad about being deceptive.
- Mystery Episode: The episode follows Helen wondering why T.D. and Martha are acting so strangely and whether T.D. cheated on a math quiz.
- Names to Run Away from Really Fast: The villain in Helen's book is called Robbing Robin.
- Non Sequitur: The statement T.D. mishears Mrs. Clusky saying doesn't make sense:Mrs. Clusky: "Lollipop crocodile underpants. Skateboard cotton candy on teddy bear."
- O.O.C. Is Serious Business:
- When T.D., who's usually very Book Dumb, gets an A in math (and not only that, he's the only student to do well on a math test), everyone's surprised and confused.
- Helen notes that it's particularly odd that Martha apparently lied to her, since she's her dog, and she usually doesn't lie.
- Right for the Wrong Reasons: Helen sees T.D. being handed an envelope and assumes that he cheated on the math test, the envelope contains the quiz answers, and this is his big secret. It turns out that the envelope does contain a secret, but the envelope does not contain the quiz answers: it's a comic book he reads despite feeling too old.
- Stock Animal Diet: Exploited — T.D. bribes Martha and Francois with hot dogs.
- Stock Animal Name: Martha's codename is Sparky.
- Sweet Polly Oliver: Discussed when Martha fears that she can't go home and will have to grow a moustache, pretend to be male, and change her name to Marty.
- Title Drop: When Helen sees T.D. and the other boy being suspicious in the park, Helen says, "This is the big secret you've been looking for: the cheating chum caper!".
- Unmanly Secret: The "childish secret" variant shows up when T.D. is embarrassed to admit he reads a comic book called The Love Bugs, because he thinks it's "for little kids".
- Will Not Tell a Lie: Discussed when Helen notes that it'd be very strange if Martha lied.
