|“||Just look at us, we're all fused together.||”|
— Candace Flynn
Candace realizes that she needs to spend more time with Stacy, so she vows to spend the whole day with her only. But while visiting Jeremy and his mom, Mrs. Johnson, Dr. Doofenshmirtz's "Combine-inator" zaps her and Jeremy, literally joining them at the hip. Meanwhile, Phineas and Ferb build a giant robot dog that causes a lot of mischief.
Candace is on her cell phone talking to Stacy about Jeremy. Suddenly Candace realizes that she is not actually talking to Stacy, but a recording of Stacy saying "uh huh" played over and over. Stacy picks up the phone to tell Candace that she is sick of listening to her talk about Jeremy and misses hanging out with her. Candace, feeling guilty about neglecting her best friend, tells Stacy that she will cancel her date with Jeremy so that they can go to the Danville Street Fair together. Stacy makes Candace promise that there will be no mention of Jeremy throughout the day. Candace says goodbye to Stacy and starts to call Jeremy, but instead she decides to go and tell him in person.
Meanwhile, Isabella decides that this will be the day that she will insist on spending time with Phineas alone. She enters their yard to see that Phineas and Ferb are working on building a giant robot dog (later named Rover). Baljeet points out the similarity to the title sequence; and Buford says he would rather give a monkey a shower. Isabella asks Phineas if he wants to go the new Stumbleberry Finkbat movie. Phineas says okay, but Ferb says he would also like to go to the movies. Isabella, wanting to spend the movie alone with Phineas, says that she has only one extra ticket and the movie is sold out. Phineas tells her that they will go after they finish the robot dog and wonders where Perry is.
At Doofenshmirtz Evil Incorporated, Perry has already been captured with robotic arms restraining every limb of his body, and his head. Dr. Doofenshmirtz explains that during his childhood in Gimmelshtump that the only things that make him happy were his giant pet cockroach and garlic ice cream. He wondered if merging the two together would make him even happier, and from that childhood idea came his latest invention, the Combine-inator. With his invention, he finally merges the two things to create "the triple-scoop garlic roach cone". Perry is rather horrified by the creation, and even Dr. Doofenshmirtz looks uncomfortable when it moans "so cold..." Doofenshmirtz drops his creation, causing it to say "Ow", quickly forgetting about it, and begins to tell Perry about his latest plan. He will use the Combine-inator to combine the little island timeshare he owns with the capital of the Tri-State Area. This, he claims, will make him ruler of the Tri-State Area. (As long as he fills out the appropriate paperwork in time.) Perry escapes from his trap and attacks Doofenshmirtz.
Candace has arrived at Jeremy's house, and is greeted by Mrs. Johnson. She tells Candace that Jeremy is tired out from working all day and night at Slushy Burger, and is fast asleep on the couch, not likely to wake up for a long time. Candace sits next to Jeremy to try to wake him up. A stray beam from the Combine-inator is split by a giant prism, one half hits a satellite (which absorbs the beam) and the other half heads straight for Candace and Jeremy, joining them at the hip. Candace worries about what Stacy will do, now that they might not be able to spend the day together. She assumes that the problem must be caused by Phineas and Ferb.
Meanwhile, back at the Flynn-Fletcher house, Isabella watches in disapproving frustration as Phineas checks things off his checklist for the robot dog. Phineas tells her that the dog is finished so they can finally go see their movie. However, Candace storms in, demanding help. After a few other suggestions, Phineas decides that the best thing to do would be to recreate the Molecular Separator, to Isabella's frustration. Candace runs off to the Cafe to meet Stacy.
Back at Doofenshmirtz Evil Inc., Perry and Doofenshmirtz have reached a stalemate until Norm enters, and Doofenshmirtz used the Combine-inator to create "Normenshmirtz", a two headed robot, giving him the upper hand.
Candace arrives at the coffee shop, dragging the still-sleeping Jeremy along on a skateboard. She sees Stacy coming and hides Jeremy under a tablecloth, disguising him as a table. Stacy orders them iced tea, and sits down with Candace at the Jeremy-table. Candace struggles to keep Jeremy hidden while they talk, and Stacy wonders why Candace is acting so strange. When Stacy goes to pay for their drinks, Candace hides Jeremy under a trench coat. They leave the cafe to go to the street fair.
Perry and Normenshmirtz are still fighting, and a beam from the Combine-inator fuses Perry with a toolbox, giving him a red toolbox body and tools for limbs. Now Perry has the advantage.
Meanwhile Phineas and Ferb have finished constructing the Molecular Separator, and Isabella is happy to hear that she can go to the movies with Phineas as soon as they bring the machine to Candace. Unfortunately, Rover grabs the Molecular Separator and runs off with the kids chasing after him. At the Danville Street Fair, Stacy and Candace are spending time together to the song Just the Two of Us. Candace continues to try to keep Jeremy hidden from Stacy.
Perry leaps up onto Normenshmirtz and uses his screwdriver arm to remove Normenshmirtz's arm. Perry uses the arm to fire at Normenshmirtz, but misses so he just throws the arm, knocking Normenshmirtz into the Combine-inator, sending off another blast and combining Toolbox-Perry with Doofenshmirtz's trap. Normenshmirtz accidentally breaks the lever (which was apparently made out of balsa wood) off of the Combine-inator. This causes the machine to lock into overload, sending random blasts in all directions and combining Normenshmirtz with a refrigerator.
The kids follow Rover into the Danville Street Fair, and they split up to try to corner him. Candace is wandering around the street fair, looking for a place to hide Jeremy. She puts him in a dressing booth, pulling the curtain to hide him. Stacy comes up and wants to go into the dressing room to try on some clothes. Candace tries to prevent Stacy from entering the dressing booth so she won't see Jeremy.
Ferb catches up to Rover and pulls out some wires in his leg to shut him off. Rover drops the Molecular Separator, smashing it. The broken machine sends out a shock wave, undoing all of the effects of the Combine-inator.
Stacy angrily pulls back the curtain of the dressing booth and Candace apologizes and starts to explain before looking in the dressing room to see that Jeremy is not there. Stacy enters the dressing room to try on the clothes. Jeremy walks out from behind the dressing booth and asks Candace if she knows how he got to the street fair. Candace tells him that she will explain later but he has to leave for now. After he leaves, Stacy sticks her head out of the dressing booth and tells Candace that she had known the whole time that Jeremy had been there.
Now that Candace and Jeremy are separated, Phineas and Isabella prepare to go to see a movie. Phineas says goodbye to Ferb. The satellite that had been hit earlier releases its half of the Combine-inator beam, hitting Phineas and Ferb. Isabella is horrified by the combined Phineas and Ferb. "Does this mean we can all go now?" He asks in Phineas's voice. In Ferb's voice, he replies, "Yes, yes it does."
- The giant robot dog seen in the theme song montage makes its first episode appearance.
- This is the first episode that when "Hey, Where's Perry?" is asked, Doofenshmirtz already has Perry trapped.
- Baljeet breaks the fourth wall twice:
- First, when he mentioned how they made the title sequence, with Buford mentioning that he prefers to give a monkey a shower, which was also in the title sequence.
- Second, he also asks how everyone is running in slow motion, and he's not.
- The beam from the Combine-inator has what looks like a DNA strand running through it.
- First episode in Season 3 that Linda does not appear nor mentioned.
- Eighth episode with Candace's name in it ("Lights, Candace, Action!", "Candace Loses Her Head", "Journey to the Center of Candace", "Oil on Candace", "Cheer Up Candace", "Candace's Big Day", "Candace Gets Busted").
- The fair's background music sounds similar to the one that was heard when Phineas and Ferb were in Mitch's ship ("The Chronicles of Meap").
- Baljeet and Buford break the 4th wall, when they talk about the opening titles.
- This is the second episode that Isabella ask Phineas out to go somewhere and ends up going with both him and Ferb ("Out to Launch").
- The triple-scoop garlic roach cone and later Dr. Doofenshmirtz says "So cold..." like Baljeet in Hide and Seek.
- Second time Major Monogram is neither seen nor mentioned ("Isabella and the Temple of Sap").
- Third time Perry didn't interact with Major Monogram ("Hail Doofania!", "What Do It Do?").
- Isabella says "Oh, Phineas!" again. ("That Sinking Feeling", "Phineas and Ferb Summer Belongs to You!")
- The trap Doofenshmirtz traps Perry in resembles the portal to Mars from Unfair Science Fair.
- Second time Phineas and Ferb repeat a project ("Rollercoaster: The Musical!").
- Isabella mentions Stumbleberry Finkbat, of which Ferb, Buford, Albert and the Unnamed Pinhead Pierre actress role played once ("Nerds of a Feather").
- This episode along with "The Great Indoors" were the first episodes aired for Season 3.
- This episode aired on Disney Channel on Demand February 28, 2011.
- First time since "Nerds of a Feather" the production studio is identified as "Disney Television Animation" in the credits.
- April 14, 2011 (Disney Channel Brazil)
- April 25, 2011 (Family Channel)
- May 1, 2011 (Disney Channel Asia)
- May 10, 2011 (Disney XD UK)
- June 1, 2011 (Disney XD Canada)
- June 13, 2011 (Disney XD Italy)
- September 17, 2011 (Disney XD Poland)
- September 17, 2011 (Disney XD Turkey)
- September 24, 2011 (Disney Channel Poland)
- September 25, 2011 (Disney XD Spain)
- October 15, 2011 (Disney Channel Spain and Portugal)
- October 18, 2011 (Disney XD Germany)
- November 11, 2011 (Disney Channel Scandinavia)
- Sometimes, Stacy's shirt fold is on the right side of her shirt or is on the left instead.
- Baljeet says, "Like when we made that title sequence". However, neither Baljeet nor Buford appear in the title sequence.
- When Dr. Doofenshmirtz is combined with Norm, Doofenshmirtz's hands are on the top-left position and bottom right position while Norm's are on the top right position, and bottom left position. But when Doofenshmirtz says "You can't get away from me now hahahaha", the arms instantly switch positions. But they are back where they originally were when Perry is combined with the toolbox.
- When Isabella says "What are we waiting for?", her eyebrows become thick, like in "The Chronicles of Meap".
- In a part of the song, Jeremy was hanging off the clothes of Candace in the game, but Candace should fall with him due to Jeremy's weight, but Candace didn't.
- When the Combine-inator hits two things, they are merged and look like a combination of the things that were combined and also function as one thing together. However when Candace and Jeremy were hit, Jeremy was just attached to Candace's hip and they functioned as two separate people due to this.
- This discrepancy can be easily explained if you just remember that the beam was split by a giant prism before it hit Candace and Jeremy. Since they only got half the beam, they were only partially fused. The other half hit a satellite, which began to slowly charge the captured beam. When the satellite fired at Phineas and Ferb, the beam had been charging long enough to be back at full strength and thus, fully fused the two brothers. Likewise, it is also possible that the fusion is different each time.
- Buford mentions giving a monkey a shower ("Swiss Family Phineas").
- The characters mention the time Candace got separated and rebuild the molecular splitter ("Split Personality").
- The Fly - The idea of a two people or objects being fused into one could've been inspired by many old sci-fi/horror films, such as '"The Fly".
- The manner of which Jeremy and Candace are fused together (as opposed to all of the Combine-inator's other targets, which seem to bond completely), seems to allude to the expression, "attached at the hip."
- The Simpsons - Jeremy was sleeping in a manner as Homer Simpson with a beer and a donut in the couch.
- Weekend at Bernie's - Candace walking around with a sleeping Jeremy and hiding him could be inspired by the movie "Weekend at Bernie's".
- Combining names like this is a common way to refer to romantic pairings in a fandom, such as this very wiki.
- Catch-22 -In the Joseph Heller novel, a critically wounded soldier repeats the phrase "So cold. So cold", as he lies dying in Capt. Yossarian's arms.
- Vincent Martella as Phineas
- Ashley Tisdale as Candace
- Thomas Sangster as Ferb
- Caroline Rhea as Linda ♦
- Mitchel Musso as Jeremy
- Dan Povenmire as Dr. Doofenshmirtz, Additional Voices
- Dee Bradley Baker as Perry, Additional Voices
- Jane Lynch as Mrs. Johnson
- Bobby Gaylor as Buford
- Maulik Pancholy as Baljeet
- Alyson Stoner as Isabella
- Kelly Hu as Stacy
- John Viener as Norm, Additional Voices
- Jeff "Swampy" Marsh as Major Monogram ♦
- Additional voices: Corey Burton, Carlos Alazraqui, Madison Pettis, Andres Cantor, Erik Estrada, Ariel Winter
♦ designates a character that did not play in this episode
"The Great Indoors"
"Run, Candace, Run"