Brendan Vu, a front-runner in the Regional Spelling Bee collapses during the competition, and Shawn and Gus must investigate the sabotage (much to Gus's excitement). The chief wants them to question all the remaining contestants and solve the case before the end of the contest. The plot thickens with the spellmaster Elvin Cavanaugh's mysterious death, which occurs right before he is supposed to make a big announcement. The police think that the evidence points to a heart attack or an allergic reaction, while Shawn suspects foul play. Gus finds out that Jiri Prochazka, another contestant, has an inhaler identical to Brendan Vu's, and that the doctor on Jiri's prescription is a fake. After sneaking into the spellmaster's box a couple of times, Shawn and Gus conclude that Cavanaugh was poisoned and discover that he had been watching Jiri's father, Miklous. Shawn catches Miklous sending signals to his son through a fake inhaler during the competition, and solves the case. Brendan Vu accidentally got a hold of the fake inhaler, Cavanaugh caught Miklous cheating, and Miklous poisoned Cavanaugh to cover it up.
*Lassiter has a new partner, Juliet O'Hara, and she stole Shawn's seat in a diner.
*Shawn finds out that Gus is an expert when it comes to spelling bees, and that he TiVos the competitions.
*Shawn needs a favor from Henry, and has to build a doghouse to get it.
1989: Gus is a contestant in a spelling bee. He nervously tries to spell his word (aggiornamento), but loses when he looks to Shawn, who gives him the wrong letter. We later find out that Shawn intentionally gave Gus the wrong letter, so that Gus wouldn't have devoted all his time to studying for spelling bees. We also see that Gus is still very bitter about losing.
1989: Shawn wants a dog, and Henry tells him that he must build a doghouse first. The flashback continues later on, when Henry comes home and is unsatisfied with the result. Later (in present time), Shawn needs his dad to get the spellmaster's food lab-tested, and must finish the doghouse for that to happen. Henry is once again unsatisfied, but this time around Shawn doesn't give up on it. They finish the doghouse together, and Shawn thinks that his dad helping is weird.
Shawn: Well, it's nice to meet you, Juliet.
Shawn (as Juliet): (in a very high-pitched voice) It's nice to meet you, too, Shawn, And I'm sorry about your seat, so lunch is on me. So, what do you do for a living?
Shawn: A little bit of everything.
Shawn (as Juliet): That sounds interesting, and maybe a little dangerous. Oh, I like your jacket.
Gus: And I don't care what you think, Shawn. I watch the Bee-Semis every year.
Shawn: Okay, for your sake and mine, stop giving the spelling bee hip little nicknames!
Shawn: How come I can't get you this excited about girls? Or Mexico?
Gus: Can you spell any of these words?
Shawn: Proudly, I've never heard of any of these words. I file them under "things to say when I wanna be ridiculed or kicked out of bed."
Gus: See, the problem is that but butyraceous is clearly a round one word.
Shawn: Oh God, please stop talking. I'd like to pretend that we still have things in common, Gus.
Gus: (RE: the spelling bee) And it teaches grace under pressure. Poise. Dignity.
Shawn: All things you could get at a hot dog eating competition. Plus...hot dogs.
Shawn: Okay, not to belittle this guy's life, but this just got more interesting than the wood-carving finals.
Lassiter: Come on. You can introduce me to the press.
Juliet: Okay. Just be sensitive.
Lassiter: How 'bout we don't sell the seat the guy landed on?
Shawn: Gus! You have got to stop calling your nose "The Supersmeller." If you wanna nickname a body part, nickname your butt, man! Call it the "Tightbouncer" or the "Hexagon." Ladies are gonna dig that. I'm telling you.
Shawn: I need to know what this is.
Henry: Looks like a number 15 with chicken.
Shawn: Dad, you made a joke!
Shawn: A yellow fruit. Also, a kind of pudding, a delicious pudding.
Speller: Sentence, please?
Shawn: Anna Banana would like to hear "Venus" by Bananarama. Banana.
Shawn: Mitchum.
Speller: Mitchum?
Shawn: Yes. When I go to Albertson's, I have to buy Mitchum ice blast...and bananas.
Lassiter: Want me to cuff him?
Chief Vick: Why? Why would I want that?
Lassiter: Just a suggestion.