Phineas and Ferb investigate the myth of the legendary "Lake Nose Monster", an inhabitant of Lake Nose. Meanwhile, Doofenshmirtz uses a machine to filter all of the zinc out of the water of the lake, even though he experiences trouble thinking of an evil scheme that could involve zinc, and Candace gets a job as a lifeguard on the lake's beach when Jeremy also works there as a lifeguard. ("The Lake Nose Monster")
Phineas and Ferb build a translator to see if Perry's chattering noises actually mean anything, but they discover it can work on other animals too. Meanwhile, Doofenshmirtz tries to flood the Tri-State Area so he can make it like Venice and force everyone to buy his new Buoyancy Operated Aquatic Transport, or BO-AT for short. ("Interview With a Platypus")
Phineas and Ferb learn what the word "aglet" means and try to spread awareness of this to the world, while a disbelieving Candace and her best friend Stacy use the campaign as an opportunity to become famous. Meanwhile, Doofenshmirtz tries to get an embarrassing video of himself skating into a toilet off the internet by erasing the world's memory of its existence. ("Tip of the Day")
Candace uses a growth elixir Phineas and Ferb created to become tall enough to audition for a modeling career at a local festival, but becomes a 50-foot giant as a result, causing an argument over her between the festival's modeling audition lady and an eccentric oddball show owner. Meanwhile, Doofenshmirtz plots to cover the festival with the smell of dirty diapers. ("Attack of the 50 Foot Sister")
Phineas and Ferb build a giant aquarium in their backyard for their new goldfish. Meanwhile, Candace awaits a phone call from Jeremy, and Doofenshmirtz plots to disrupt the hot dog vendors of Danville so he can force them to sell bratwurst. ("Backyard Aquarium")
The boys are inspired to make gelatin in their pool after Candace tells them to do something with their dessert. But, when Dr. Doofenshmirtz demonstrates his newest invention, the "Turn Everything Evil-inator", it literally brings the gelatin to life. ("Day of the Living Gelatin")
The family and Stacy visit London, where Stacy and Candace investigate the boys' newest scheme (a water slide from the top of Big Ben that ends on the London Eye) in the style of Sherlock Holmes. Meanwhile, Perry collaborates with a James Bond-esque British spy, Double 0-0 or 00 0, to foil Dr. Doofenshmirtz's plan to move Big Ben to Danville as an alternative to reading his tiny watch. ("Elementary My Dear Stacy")
Candace tries to figure out where all of Phineas and Ferb's creations go. Meanwhile, Doofenshmirtz experiments with a ray that can make things invisible. ("Don't Even Blink")
Phineas and Ferb open a platypus themed restaurant in their backyard, which quickly becomes the trendiest restaurant in town. Jeremy takes Candace there, but both of them have to deal with Buford who refuses to let them in. Meanwhile, Doofenshmirtz goes on a date at the restaurant with a woman also interested in evil, but threatens to use a satellite to eliminate all love in the Tri-State Area if it doesn't go well. The date goes well and before they can kiss, the love satellite crashes and changes her feelings towards him, making her dump him. ("Chez Platypus")
When Phineas and Ferb find an egg, they believe it belongs to Perry, so they build a mechanical contraption to care for it. When Candace sees what her brothers are doing, her maternal instincts emerge and she agrees to help, on the condition that they do things her way. Meanwhile, Doofenshmirtz plots revenge on whales who told his girlfriend to dump him by means of a whale translation device he created. ("Perry Lays an Egg")
Phineas and Ferb create their own video game and program themselves into it. When Candace is accidentally zapped into the game, Phineas and Ferb have to bring her back in time for her cotillion. Meanwhile, Doofenshmirtz creates a device that can put ball gowns onto people to make them girlier (which would make him manlier by comparison). ("Gaming the System")
When the boys accidentally knock a spacecraft out of the air with a remote-controlled baseball, Candace discovers an alien named Meap, who she initially believes is a plush toy that had been "robotized" by her brothers. But when Phineas, Ferb and Isabella are captured by Mitch, an alien poacher trying to capture the "cute" creature, Candace and Meap are forced to help rescue them. Meanwhile, when Dr. Doofenshmirtz tries to retrieve a balloon he had treated as a friend in his childhood using static electricity, he and Perry are launched into the crossfire of the battle with Mitch. ("The Chronicles of Meap")
When Candace meets Mandy, the sister of a pair of brothers who also like to build ambitious projects, the two ultimately force their brothers to compete in building forts. Meanwhile at a family reunion, Dr. Doofenshmirtz tries to win a game of kickball with a robotic kicking leg. ("Thaddeus and Thor")
Phineas and Ferb built a passenger plane out of paper-mâché to beat the record of the longest wingspan held by the famous Spruce Goose. Meanwhile, at the pool party at Jeremy's house, Candace and her best friend Stacy see an Australian girl named Nicolette who seems to be trying to gain Jeremy's attention (Candace and her best friend Stacy doesn't know that Nicolette is actually Jeremy's cousin), and Doofenshmirtz builds an evaporation machine out of recycled materials. ("De Plane! De Plane!")
When Candace learns Jeremy is going to appear in a television commercial, she decides to compete against Buford in a game show Phineas and Ferb are producing. Meanwhile, Doofenshmirtz plots to melt local television station towers to curb an addiction to ordering products from infomercials. ("Let's Take a Quiz!")
Phineas and Ferb help Isabella and the Fireside Girls meet their fundraising goals by building the world's most elaborate automatic car wash. Candace ignores Stacy's advice to play "hard to get" to Jeremy when he invites for a ride in his mother's car to the boys' car wash. Doofenshmirtz tries to literally make mountains out of molehills. ("At the Car Wash")
When Perry is reassigned to a new villain after Dr. Doofenshmirtz is downgraded to a low-level threat, he is ordered to leave the Flynn-Fletcher household and relocate to the new villain's area; the boys believe Perry has gone missing and try to find him. Meanwhile, after learning of his downgrade, Dr. Doofenshmirtz confront Perry's new nemesis, but ends up accepting an internship with the new villain. Because she kicked him out of the house after tripping over him, Candace blames herself for Perry's disappearance and works with the gang to get Perry back. ("Oh, There You Are, Perry")
After becoming marooned on an island after a storm, Phineas and Ferb build an elaborate island tree house as a shelter. Candace goes freaky with getting back home because she wants to get to Jeremy's party on time. Meanwhile in an inactive volcano on the island, Dr. Doofenshmirtz enslaves monkeys to help him start a laundry cleaning business so he can eventually replace all the laundromats in the Tri-State Area with a franchise of "Evilology" institutes. However, Perry's mission to stop him becomes delayed when Baljeet was asked to take care of him during his owners' absence. ("Swiss Family Phineas")
Candace tries to bust her brothers when, to play a game of indoor hide and seek, Phineas and Ferb shrink themselves and their friends down including their new extreme fan, Irving. Meanwhile, Dr. Doofenshmirtz attaches a nanobot to Perry in an attempt to discover where he lives. ("Hide and Seek")
Baljeet wants to impress his childhood friend from India, so he enlists Phineas and Ferb to help woo her. However, none of their over-the-top romantic gestures impress her, as she likes Baljeet for who he really is. Meanwhile, Perry must stop the sleep deprived Dr. Doofenshmirtz from moving the Danville Lighthouse to the other side of town so that he isn't bothered by all the ships. ("That Sinking Feeling")
Baljeet enlists the help of Phineas and Ferb to create a song to perform at a summer camp concert, Candace sets Stacy up with Coltrane, while also getting frustrated that Jeremy didn't give her a nickname, Doofenshmirtz plots to create an army of babies by broadcasting his heartbeat across the city on a speaker. ("The Baljeatles")
Dr. Doofenshmirtz gives his daughter Vanessa an assignment to retrieve a container at a mall containing a rare element for him to prove she is responsible enough to have her own car (and so Doofenshmirtz can experiment with it), but Perry (who is trying to get it away from Dr. Doofenshmirtz), Baljeet (who wants to use it in a science project), and Candace (who thinks the item is a lantern she can give to Jeremy) are also trying to get the capsule. Meanwhile, Phineas spends the entire episode relaxing in a massage chair while Ferb is helping Vanessa retrieve the container. ("Vanessassary Roughness")
Candace finds a rabbit outside her house and decides to take it in as a pet. However, the rabbit is actually a rogue agent named Dennis, whom Perry is trying to prevent from hacking into the Agency's mainframe. Meanwhile, Phineas and Ferb develop actual X-ray glasses after being ripped off by a novelty variety, and due to Perry's absence Dr. Doofenshmirtz appoints a potted plant as his nemesis. ("No More Bunny Business")
Candace becomes sidetracked from a scheduled spa appointment and forces Stacy to work at a construction site with her because Jeremy is there, and the boys create their own spa to help make up for the missed appointment. Meanwhile, a stray cat Dr. Doofenshmirtz takes in as a pet causes chaos in his lab. ("Spa Day")
After encountering them in the future, an older version of Candace decides to steal Phineas and Ferb's time machine and go back in time to the day they built a rollercoaster[a] so she can help the present Candace catch them in the act. But when her actions cause a chain reaction turning the future into a dystopian society led by Dr. Doofenshmirtz, the future Candace decides to enlist her present brothers to help restore the good future. ("Phineas and Ferb's Quantum Boogaloo")
Major Monogram and Dr. Doofenshmirtz present a viewer-voted countdown of songs from Season 1, while Doofenshmirtz himself plots to take over the world with a song that is scientifically engineered to permanently become stuck in the mind. ("Phineas and Ferb's Musical Cliptastic Countdown")
When Phineas and Ferb create the largest and most durable bubble ever, they, the Fireside Girls, Buford and Baljeet get trapped inside it flying around the city. Meanwhile, Candace practices driving and Dr. Doofenshmirtz uses a voice-altering cowboy hat to help him spread propaganda through country-and-western music. ("Bubble Boys")
In a side story of the previous episode, Isabella and her Fireside Girls troop try to retrieve a rare variety of tree sap for Phineas and Ferb's bubble project from an abandoned amusement park. Meanwhile, Pinky the Chihuahua's nemesis Professor Poofenplotz tries to steal a supply of her favorite, but discontinued hair spray. ("Isabella and the Temple of Sap")
After feeling depressed when Jeremy cancels his date with her, Phineas and Ferb try to cheer Candace up. Meanwhile, Perry is discharged from the agency after he is accused of a series of crimes, only though he later discovers that Dr. Doofenshmirtz has framed Perry using various different clones of him. ("Cheer Up, Candace")
Candace joins the Fireside Girls and tries to get 50 patches in one day so she can get tickets to see a Paisley Sideburn Brothers performance at their jamboree. Meanwhile, Dr. Doofenshmirtz tries to halt Fireside Girls cupcake sales by using a device that can turn things into broccoli, including the factory where the cupcakes are made. ("Fireside Girl Jamboree")
Buford vows to become Baljeet's slave after he saves Buford from choking on a hot dog while eating four at once. Meanwhile, Candace tries to prevent Jeremy from seeing embarrassing photos she accidentally sent to his cell phone, and Dr. Doofenshmirtz tries to get back at an ice cream truck driver who drove over his foot. ("The Bully Code")
When Lawrence accidentally sells Candace's Little Mary McGuffin doll to Dr. Doofenshmirtz as a gift for his daughter Vanessa, Phineas and Ferb try to investigate it like movie and TV detectives. Meanwhile, Dr. Doofenshmirtz tries to retrieve a working on-off switch for his newest device. ("Finding Mary McGuffin")
When Phineas and Ferb create a teleporter that can retrieve objects from anywhere by scanning in photographs, Candace tries to expose it to Linda by teleporting her back from a Mexican-Jewish cultural festival. Meanwhile, Dr. Doofenshmirtz tries to rid the world of mimes by trapping them in actual invisible boxes. ("Picture This")
Jeremy is unsure of his own dancing skills when he agrees to partner with Candace on the popular television show Let's All Dance Until We're Sick, so the boys develop an exoskeleton allowing Jeremy's movements to be controlled by Ferb. Meanwhile, Dr. Doofenshmirtz and his organization of other mad scientists try to get an evil message broadcast on the show. ("Nerdy Dancin'")
When one of Doofenshmirtz's inventions lands in their front yard, Phineas and Ferb try to figure out what it does. Meanwhile, Dr. Doofenshmirtz and Perry get trapped on board Doof's Floating Platform as it goes out of control with no one steering. ("What Do It Do?")
On a trip to the beach, Phineas and Ferb discover the lost city of Atlantis, Candace enters a sand castle building contest judged by Jeremy and Dr. Doofenshmirtz tries to use a growth formula to turn plants evil. ("Atlantis")
After Phineas, Ferb and their friends help decorate the city to celebrate the arrival of Santa Claus, Dr. Doofenshmirtz, after finally finding a reason to hate Christmas, uses his Naughty-inator to try to ruin the holiday for everyone. As a result, the boys and their friends try to help save Christmas for Danville. ("Phineas and Ferb Christmas Vacation")
When Phineas and Ferb create an orb that allows its user to pass through objects to help find Linda's lucky guitar pick, Candace attempts to bust her brothers with it. Meanwhile, Dr. Doofenshmirtz tries to destroy a statue honoring his brother Roger. ("Just Passing Through")
When Phineas and Ferb offer to host Aunt Tiana and Uncle Bob's wedding in the Flynn-Fletcher's backyard, Candace tries to prevent the boys from messing up the wedding and stealing attention away from her role as maid of honor. Meanwhile, Dr. Doofenshmirtz builds a device to turn all healthy foods in the city into junk food, believing that overweight people would be easier to enslave. ("Candace's Big Day")
Lawrence's memory is accidentally erased by a gadget in Perry's lair before participating in a father-daughter race with Candace, so Perry operates a robot version of Lawrence to fill in for him. Meanwhile, Dr. Doofenshmirtz invents "Eulg", an opposite of glue, which breaks stuff apart rather than joining it together. ("I Was a Middle-Aged Robot")
When Candace offers to babysit Suzy, Suzy tries to teach Candace how to get anything you want. Meanwhile, Phineas Ferb, and friends try to build a giant waterfall and ride a barrel over it. Meanwhile, Dr. Doofenshmirtz builds a giant foot out of carbon paper believing that it'll increase his carbon footprint. ("Suddenly Suzy")
When the boys build an Anti-Gravity Fun Launcher, Carl accidentally discovers their plans on the internet and presumes they are working for Dr. Doofenshmirtz, so he is sent undercover to figure out what they are doing. Meanwhile, Doofenshmirtz intercepts the plans himself and attempts to find a use for it, and Perry is sent on a literal wild goose chase to retrieve a missing agent since he is too close to the boys to spy on them. ("Undercover Carl")
Phineas and Ferb decide to help build floats for all the neighborhood kids in the yearly "Tri-State Area Unification Day" parade, but a family grudge leads Buford to try to wreak havoc on the parade. Candace promises her mom to not care about Phineas and Ferb's activities during a mother-daughter day, but finds it difficult due to the boys' antics taking place all around her. Meanwhile, Dr. Doofenshmirtz tries to create traffic jams with a duplication device. ("Hip Hip Parade")
After watching a sci-fi movie marathon, Candace becomes convinced that Ferb is an alien. Meanwhile, Dr. Doofenshmirtz plans to auction off an old invention, the Wrapped-Up-In-A-Nice-Little-Bow-Inator (which compresses objects into small wrapped boxes) by marketing it as a cleaning device. ("Invasion of the Ferb Snatchers")
When the boys trick out the kiddie rides at a store, Candace steps into the rocket ride and is sent shooting across Danville and the gang goes out on a rescue mission to save her. Meanwhile, Dr. Doofenshmirtz tries to burn his name into the atmosphere to maintain his legacy. ("Ain't No Kiddie Ride")
Irving's brother Albert doesn't believe that Phineas and Ferb are anything special, and since he claims to be the "Truth Detector", he can prove it. Desperate to prove Albert wrong, Irving convinces Baljeet and Buford to pose as Phineas and Ferb beside a giant hologram of the boys' Eiffel Tower construction, while the real Phineas and Ferb go with their father to the movies. Meanwhile, Dr. Doofenshmirtz is fed up with the quality of accessories for his model train set and decides to shrink down a variety of national monuments to add to his collection. ("Not Phineas and Ferb")
Candace, Stacy and Jenny team up to try to bust Phineas and Ferb together, while Phineas and Ferb build giant mechanical spinning tops. Meanwhile, Dr. Doofenshmirtz enlists a new robot to replace Norm, but a power surge from Phineas and Ferb's power source causes it to glitch and turn against him. ("Phineas and Ferb-Busters!")
Phineas and Ferb discover a chameleon that they decide to keep as a pet, but when it grows to a gigantic size due to the effects of one of Doofenshmirtz's inventions, Phineas, Ferb and Isabella try to get him back, although his camouflage makes him hard to spot. Meanwhile, Doofenshmirtz learns to play guitar from Jeremy so he can use a song to summon an alien army with his Every-Directional-Amplifinator Gigantinator. ("The Lizard Whisperer")
Phineas and Ferb hold a rodeo in the backyard with robotic bulls so Isabella's Fireside Girls can get a Rodeo Clown Patch while Candace tries to keep focused to go to the concert with Stacy. Meanwhile, Dr. Doofenshmirtz competes against members of L.O.V.E.M.U.F.F.I.N. and others in an Inator Creator competition. ("Robot Rodeo")
When Phineas and Ferb build a super suit, they decide to become a superhero called "The Beak" to defeat a new villain named Khaka Peü Peü. But when Phineas keeps leaving to be The Beak, drama starts between him and Isabella. Meanwhile, Dr. Doofenshmirtz is temporarily given the mayoral post by his brother Roger to prevent Roger from being blamed for Khaka Peü Peü's presence. ("The Beak")
Candace is awarded the opportunity to be mayor for the day, so she abuses her newfound power to create laws that can bust her brothers. Back at home, Phineas and Ferb build an authentic log cabin and pioneer village without modern tools. Meanwhile, Dr. Doofenshmirtz is scheduled to play golf with his brother Roger but isn't happy about it. ("She's the Mayor")
Phineas and Ferb build the ultimate lemonade stand and begin to offer franchise opportunities. Meanwhile, Candace and Stacy's relationship is put to the test when Candace feels she must pick between their friendship and busting her brothers, while Dr. Doofenshmirtz creates a "Paper-Cut-Inator" so that he can make millions selling Band-Aids. ("The Lemonade Stand")
In a half-hour episode split into two parts, the Flynn-Fletcher Family go on a vacation to Hawaii. In the first part, Phineas and Ferb make living sea creatures, and Doofenshmirtz creates a De-Evolution-inator. In the second part, Phineas and Ferb help Candace get rid of a lava necklace of bad luck, and Perry and Doofenshmirtz get stranded on an island. (Phineas and Ferb Hawaiian Vacation")
It's the summer solstice, so Phineas, Ferb, and their friends decide to travel around the world in one day in an effort to create the "biggest, longest, funnest summer day of all time". But not everyone believes they can actually achieve what they have set out to do, especially Buford. Candace tags along because Jeremy is on a trip to Paris, and she fears that there he may meet other girls. Also, Isabella finds her affections for Phineas sorely tested when his steadfast focus on achieving his goal puts pressure on her. Meanwhile, Dr. Doofenshmirtz takes a father trip to Tokyo, Japan with Vanessa, but sets out with Perry and Major Monogram to find her when she joins Phineas, Ferb and the others. ("Phineas and Ferb: Summer Belongs to You")
Phineas and Ferb head to the Tri-State area's annual sci-fi/fantasy convention to meet their hero, special effects guru Clive Addison. Their plan gets sidetracked when they're swept into a duel between Buford and Baljeet, and their respective clubs of fantasy fans and sci-fi geeks. Meanwhile, Candace tries to keep secret that she's a fan of Ducky Mo-Mo (which is a children's show with an adult fan base, somewhat like the bronies of the My Little Pony fandom), another convention staple. Across the convention hall, Dr. Doofenshmirtz has taken television executive Jeff McGarland hostage so he can pitch him a show he's developed, Doof 'n' Puss. ("Nerds of a Feather")
Mom says that Phineas and Ferb have to clean the house and she asks Candace to help, but she refuses and instead reads the book Mom gave her: The Wizard of Oz. Phineas and Ferb spin the house and spray it with a hose, but they spin the house too fast and accidentally knock Candace out, sending her into a Wizard of Oz-esque dream world. She journeys to "Bustopolis" under the impression the world is a simulation created by her brothers, but soon discovers that evil forces are attempting to get the boots that have grown on her feet. ("Wizard of Odd")
Phineas and Ferb build a maze to help Isabella and a junior Fireside Girl, named Melissa. Meanwhile, Dr. Doofenshmirtz tries to tilt all buildings on the tri-state area as the Leaning Tower of Pisa. ("We Call It Maze")
When Candace discovers that her mother is Lindana, Linda is invited to participate in a reunion concert of the 80s. Lawrence feels depressed because his wife is going to forget him because she will meet exciting and fun people, so Phineas and Ferb decide to turn him into "Max Modem", an unknown singer from the 80s. Meanwhile, Dr. Doofenshmirtz wants Danville to believe that he's the king and leader of a group of aliens. ("Ladies and Gentlemen, Meet Max Modem")
Phineas and Ferb build an advanced all-terrain vehicle, while Baljeet, Stacy and Candace go to a convention so Candace can improve her "busting tactics". Meanwhile, Dr. Doofenshmirtz tries to host a Telethon of Evil. ("The Secret of Success")
Phineas and Ferb build the tallest building ever to increase Danville's popularity while Candace enlists Irving's brother, Albert's help in busting them. Elsewhere, Doofenshmirtz attempts to rotate the moon to its dark side so he can become the most evil man in the world. ("The Doof Side of the Moon")
Phineas and Ferb create a machine that splits an object into its components, but their cover is blown with Candace and her double. Doofenshmirtz tries to jump off the high diving board, which was an important ritual of manhood in his hometown, that he failed. He is nervous and creates a Look away-inator, so that nobody will stare at him. ("Split Personality")
Phineas, Ferb, Isabella and Baljeet are in bed because they're sick and they, along with Buford, who is just lazy, play video games that let them compete against another friend. Doofenshmirtz creates a helmet that can control everyone who wields it. Meanwhile, Vanessa tries to enjoy her time at a Junkyard Party, despite knowing Doofenshmirtz will make her mortified. ("Brain Drain")
Phineas and Ferb relive the day they built a rollercoaster[a] as a musical. Doofenshmirtz once again tries to reverse the rotation of the Earth.[a] ("Rollercoaster: The Musical")
Candace switches places with a princess who looks just like her, but the ongoing antics of Phineas and Ferb prevent her from enjoying the royal luxuries, even for a day. Meanwhile, Phineas and Ferb enlist the princess to help them build a giant jukebox filled with live bands, and Dr. Doofenshmirtz plans on using his Claw-inator to ruin his brother's dedication of the Danville Opera House. ("Make Play")
When Linda and Lawrence go on a trip, Candace decides to have an Intimate Get Together with Stacy and Jenny. However, more people come without permission and make it into a party. Meanwhile, Doofenshmirtz tries to get rid of the condos, which block his view of the free drive-in theater nearby. ("Candace Gets Busted")