- Wubbzy's House
- Walden's House
- Wuzzleburg Streets
- Supermarket (debut)
- Marshmallow Factory (debut)
- Mount Zubba Bubba (debut)
Walden wants to make Wubbzy's birthday party perfect by baking a marshmallow lasagna, but marshmallows aren't in season.
Outside his house, Wubbzy, along with Widget, make party decorations, hats and invitations for Wubbzy's birthday party. Walden comes to check on them to see how everything's going, then asks about the 'perfecto party dish': Marshmallow lasagna. There wasn't any because marshmallows weren't in season. Wubbzy suggested having jelly bean lasagna, but Walden denies it and still wants to make marshmallow lasagna for his birthday. He leaves and tells them not to start the party until he returns.
At his house, Walden exits it and decides to make the lasagna in the wagon, connected to his car, to save time. He then drives to the supermarket.
Wubbzy goes to the playground to send party invitations to his friends, Buggy, Huggy and Earl. They all agree to come soon.
Meanwhile, Walden's at the supermarket collecting the ingredients needed to make the lasagna. He heads to the marshmallow isle, but shocked to see it completely empty. A grocer tells him that marshmallows are out of season. Walden thinks big, and decides to get marshmallows from the factory.
The party is ready to begin. Wubbzy and his invited friends are pumped up, but Widget freezes them, saying they're supposed to wait for Walden to come back. Wubbzy postpones the party, disappointing his friends.
Walden drives to the marshmallow factory, but sees a sign on the locked front gate that says "Closed for the season". He got worried and thinks even bigger. He decided to drive to and get marshmallows from the top of Mount Zubba Bubba.
Buggy, Huggy and Earl were getting bored and tired of waiting. Wubbzy and Widget weren't happy, but Wubbzy cures their boredom by having them help make his cake. With different things they can assist with, they cheerfully agree to help, buying Wubbzy and Widget time.
On top of Mount Zubba Bubba, Walden was collecting marshmallows in its trees, but didn't want to get ones that were too hard or too soft. Just 'perfecto'.
Wubbzy and Widget bring out the cake, and despite it looking floppy; Buggy, Huggy and Earl loved it when they ate fingers full of frosting. They began eating bigger pieces, making Wubbzy halt them. Expecting Widget to back him up, he sees her eating a piece, then hiding it behind her back when she agreed, annoying him.
Back on the mountain, Walden collects the rest of the 'perfecto' marshmallows and puts them in the wagon. He gets surprised when he looks at his watch, telling him he's late for Wubbzy's party. Walden hurries in the car and starts it, but the engine's too worn out for driving up the tall mountain. He then gets a brainstorm. He takes the wagon, full of his lasagna ingredients, to ride down the mountain. While it rushes him down, Walden begins making the marshmallow lasagna as he heads back to Wuzzleburg.
Although Walden hasn't arrived yet, Wubbzy and his friends start partying. Buggy, Huggy and Earl dance in a line and follow Widget while she rides Wubbzy on her back.
Walden continues blazing through town in his wagon while making the lasagna, as he unawaringly rushes by his surroundings. He enters a car wash and gets sprayed with water when he needed it. He exits the wash and the lasagna's all made.
The party ended as Wubbzy's friends complimented it. After Wubbzy apologizes for not having any lasagna, Walden storms his way to the party area with it. He finishes making it and realizes that he's heading toward his friends. They all run, except for Wubbzy who screams. Walden's wagon hits a rock and he goes flying along with the lasagna and it lands on the picnic table, and Walden lands on it. He lackadaisically gave Wubbzy a happy birthday greeting and says he's sorry for ruining his party. However, it was never ruined and everyone had a blast, even without the lasagna. Wubbzy said that friends is all you need for a 'perfecto party'. Walden agrees, then Widget adds that a big, heartful friend who brings an amazing marshmallow lasagna makes the party 'super perfecto'. Huggy and Earl want some, but Buggy, all stuffed, refused after eating half the birthday cake, making his friends laugh.
Wubbzy and Widget ate the lasagna. Widget says it's 'perfecto', but the marshmallows gave Wubbzy an allergic reaction, making orange spots appear around his body. The three laughed as orange spots cover the screen, leaving an uncovered spot over Wubbzy.
Walden: Galloping gigahertz! Where are all the marshmallows?
Walden: *Plucks marshmallow from tree* No, no, no. Too hard. *Plucks marshmallow from another tree* No, no, no. Too soft. I can only use marshmallows that are perfecto.
Buggy: *Chewing cake*
Wubbzy: Hold on, gang! We're supposed to wait for Walden. Right, Widget?
Widget: *Chewing cake, hides it behind her back* Mm-hmm.
Wubbzy: *Annoyed expression*
Walden: Who wants a piece?
Huggy: Me me me me me me me me me me!
Earl: Me me me! Me, I do, I do!
Buggy: *Groans* Not me. Oh. (Shows half the cake eaten)
Wubbzy, Widget & Walden: ... *Laughing*
Walden: Well, what do you think of my marshmallow lasagna?
Widget: I think it's perfecto.
Wubbzy: *Spots pop on all over body* I think I'm allergic to marshmallows.
Widget & Walden: ... *Laughing*
The song, "Perfect Day", is played.
Name in other languages
- Spanish (Spain): La fiesta perfecta
- Portuguese (Portugal): Uma festa perfeita
- It is revealed that Wubbzy is allergic to marshmallows when spots appear all over him. However, in "Wubbzy in the Woods" and "Tea for Three", Wubbzy eats marshmallows with no allergic reaction.
- Walden did leave his car behind at the top of Mount Zubba Bubba, but it appears in some future episodes.
- Later in some episodes, Buggy's voice sounds different from this episode and "Attack of the 50 Foot Fleegle".
- On DirecTV and other cable systems, it is stated that this episode is broadcasted before "Goo Goo Grief!", though on television, this episode is shown after Goo Goo Grief!.
- Comcast falsely claims that Wubbzy was in a search for marshmallow lasagna but however Walden was the one who was in a search for it.
- At the end of the episode, the "HAPPY BIRTHDAY WUBBZY" banner's letters were colored differently from the beginning of the episode.
- The 1st time Wubbzy makes a scream stock sound effect.
- This is the first time when a title card has something that goes off screen in the 4:3 version of Wubbzy.