As the other pets are playing, Zoe tells Penny that Digby is coming to visit The Littlest Pet Shop later that day, whom Zoe admits is hopelessly in love with. Knowing she has to look her best for her crush, she shows Penny the "freckle" on her nose, to which Penny points out that it's a gigantic zit. Zoe does not take it well. After spending some time in solitude, Penny improvises a solution the following day by wrapping gauze over Zoe's nose, but Digby happened to delay his visit by a day, forcing a run-in between him and a facially-damaged Zoe.
Blythe arrives in the pet shop and shows off her new white-with-pink-circles backpack. Russell seems particularly impressed by it and goes into an Imagine Spot about what school life must be like. He gets so excited that when Blythe has to leave for school, he sneaks his way into Blythe's backpack—as she's dashing out the store. Minka, Sunil, Vinnie, and Pepper see Russell leaving with Blythe and worry about what will happen if Mrs. Twombly finds out Russell is missing. In the other room, Zoe is still in a panic about what to do around Digby. She grabs Penny, who's standing nearby, for an idea she's just had.
On the way to school, Russell pops up out of Blythe's backpack when Blythe tells her father Roger that there are no animals allowed at the school. Blythe attempts to make excuses to return home but Roger easily deflects them all, forcing her to bring Russell to school. As she's walking in, a fire alarm accidentally rings, causing everyone to evacuate the school. In the confusion, Blythe loses her backpack with Russell in it. She scours the school and finds a white-with-pink-circles backpack, but when she opens it up, she discovers it belongs to Brittany and Whittany, her mortal enemies at school. The twins immediately find Russell in the backpack. Russell, in panic, curls into a ball and starts bouncing around everywhere like a pinball. Blythe attempts to retrieve him but the class bell rings, meaning she'll have to wait until class ends to continue looking for Russell. During class, the janitor Sawdust becomes aware of Russell running loose in the school and heads out to catch him. Sawdust finds Russell in very short order but just as easily loses him by sneaking into a classroom.
At The Littlest Pet Shop, Digby is busy exercising when Zoe requests Penny to speak to him in her place. Penny, having not had a chance to rehearse and being a Shrinking Violet to begin with, makes it clear that she's Zoe's stand-in and messes up her lines, confusing Digby.
The room Russell winds up in is the nurse's office, where Whittany and Brittany have remained since the beginning of the school day to calm their nerves. Russell accidentally falls into their line of sight, scaring the bejeebus out of them again and sending them out of the office. Because the nurse saw Russell too, he escapes the office but runs into Sawdust again, this time escaping due to Sawdust crashing into a wall due to his over-waxing the floor. At lunch, Blythe becomes increasingly delusional as she continues to unsuccessfully find Russell.
As Digby and Penny continue to talk, Digby starts enjoying Penny's company, and the two of them walk away together, filling Zoe with jealousy. Meanwhile, Mrs. Twombly announces to the pets that it's feeding time. Minka's mockup of Russell falls apart, and Vinnie, Sunil, and Pepper scramble to find a way to not let Twombly know Russell is gone. Minka desperately tries to delay Twombly from entering the room and resorts to stealing Twombly's favorite doorknob from her collection and makes her chase Minka around the room.
Blythe finally finds Russell after school, who informs Blythe that feeding time is about to begin. This alerts Blythe to getting Russell back to The Littlest Pet Shop posthaste, as Russell's owner is going to show up any minute. Blythe leaves the school and catches a taxi while accidentally helping Sawdust apprehend his real arch-enemy, a Russell lookalike who's been scouring the school's trash cans.
Zoe, perched on a stack of cushions to get a view of Digby flirting with Penny, falls to the floor on her head. Vinnie discovers Zoe's rear end in that particular posture forms a silhouette resembling Russell, so Vinnie and Sunil paint it brown as Pepper embellishes it with a pair of Groucho Marx glasses to make a facsimile of a face. Blythe's taxi gets caught in a traffic jam, so Blythe pays the cabbie and leaves on foot. She finds a bicyclist and hitchhikes with him, only to see him stop five feet in front of him. Blythe then improvises a skateboard out of scrap lumber and speeds her way back to The Littlest Pet Shop just in time for Twombly to find Russell's favorite snack. Russell leaps to catch it, knocking Zoe away. Zoe lands right in front of Digby, who compliments her for having a good friend in Penny. Before Digby leaves, he kisses Zoe's nose, leaving her elatedly satisfied for the day.
This episode contains examples of (YMMV entries go here):
- Brutal Honesty: When Digby asks why Zoe can't speak to him directly, Penny blurts out that it's because of her nose, a secret Zoe wanted to keep secret from Digby.
- Continuity Nod: Russell performs a Spin Dash right by the Biskit Twins again, this time to get away from them. Once again, the both of them freak out upon seeing him. They get it bad this time though—they continue hyperventilating well into the following act.
- Except for the cockroach, all of the creatures on Sawdust's poster of animals he exterminates have been featured in The Littlest Pet Shop merchandise, as unlikely as some may seem, including the octopus and the cobra. (The lamp doesn't count.)
- There is further mention of Mrs. Twombly's doorknob collection.
- Conspicuous CG: Roger's car is cel-shaded 3-D CG when he swerves around the road in panic.
- Crazy-Prepared: Roger apparently keeps facial wipes, a bag of cotton balls, and all four of Blythe's favorite hairbrushes in his car. Either that, or he knew Blythe forgot all of those items and put them in before bringing Blythe to school.
- Determinator: Sawdust is very persistent about getting Russell out of fear of his failure appearing in his records.
- Dramatic Irony: Blythe talks about designing a backpack that could hold a pet. Roger then tells her that she could now bring a pet to school with her. This dialogue takes place as Russell is stowed away in Blythe's backpack. This is, of course, moments before Russell emerges into Blythe's field of view.
- Everybody Laughs Ending
- Forgot About His Powers: Sunil forgets he is an illusionist, a rather useful skill in this situation, when the pets discuss how to not let Mrs. Twombly know Russell is missing.
- Furry Reminder: Zoe emits a whimper, then a growl when she hears Digby's interest in Penny.
- Innocently Insensitive: Blythe flips over another student's lunch tray in the cafeteria looking for Russell, unawarely spilling food all over the poor sap.
- Noodle Incident: Sawdust's poster suggests the school has had outbreaks of snails, tortoises, cephalopods, cobras, and lamps in the past.
- Odd Name Out: Sawdust's poster depicts a number of pest animals, plus a tableside lamp as the last item with the Littlest Pet Shop eyes superimposed over the lampshade.
- Out-of-Character Moment: The normally cautious and rule-abiding Russell stows away to school in Blythe's backpack, not even considering what could happen if Mrs Twombly were to discover his absence.
- Out of Order: The premiere dates for this episode and "Topped with Buttercream" were switched, putting "Trading Places" after it despite being made first. Reasons are difficult to pinpoint, but it was most likely to get Buttercream out sooner to sell toys of her.
- Playing Cyrano: As is natural with a plot such as this, Zoe's "blimp on her face" means Penny will have to speak in Zoe's place. Subverted in that Penny reads Zoe's lines in third-person, holds her script in plain view, and lets Digby know these are Zoe's feelings before she begins.
- Red Eyes, Take Warning: Everything on Sawdust's poster is depicted in this way.
- Screaming Woman: Zoe screams loud enough upon discovering her zit that people outside of the pet shop have to cover their ears.
- Third Line, Some Waiting: There are three plots going on in this episode: Blythe looking for Russell at school, Zoe's pimple and her affection for Digby, and the remaining pets trying to cover up for Russell's absence from the pet shop.
- What Could Possibly Go Wrong?: Russell says this word for word when he promises to stay in Blythe's locker all day.
- After losing Russell and being forced to get to class, Blythe asks herself, "How much trouble could one little hedgehog get into anyway?"
- What Happened to the Mouse?: Roger, who normally picks Blythe up from school when it ends, was never informed that Blythe returned home on her own.