The boys travel into the future to borrow a tool, but when their future sister Candace finds what they are up to, she realizes that she has the evidence she needs to travel back into the past to bust her brothers. When she returns to her own time, she realizes that she has made a terrible mistake that only she can fix.

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.

When Ferb's cousins visit from England and challenge him to a soccer match, he and Phineas warp the walls of physics and build a high tech 3D stadium. Meanwhile, convinced that her relationship with Jeremy depends on her being more proper, Candace enlists the help of Ferb's British cousin, Eliza, to teach her the rules of etiquette. Back at Doofenshmirtz Evil Inc., Dr. Doofenshmirtz is sick in couch but forces himself to set off his \"If-A-Tree-Fell-in-the-Forest-Inator\", which causes any tree that falls to say his name.

When Phineas and Ferb are inspired by an antique escape chamber that Dad acquires, they decide to build a computer-controlled tower that will trap them inside and allow them to explore the world of escapement. Meanwhile, Dr. Doofenshmirtz invents a "Rude-Inator" to ruin Roger's meeting with a visiting dignitary from England.

Candace finds it difficult to bust Phineas and Ferb when her brothers build nanobots that can assemble into any object they can imagine. Meanwhile, Dr. Doofenshmirtz has jury duty, so Norm takes over the day’s evil scheme -- to destroy Danville by using weapons.

It's time for Danville's Doo Wop Hop and car show and the whole town is getting prepped for it. Doofenshmirtz is set on winning the show even if it means using his Rust-inator to turn all the other cars into red dust. Meanwhile, Candace's hope for a car of her own has come true, but it's not quite all she imagined.

Isabella unintentionally admits her feelings for Phineas in a letter. Meanwhile, Doof invents an inator to help change his misfortune

Stacy takes on an agent role with OWCA to rescue Perry from some evil scientists.

Candace ignores her brothers for a day in order to help her Mom with a bust of her own.

A musical in which Phineas and Ferb revisit the day they built a gigantic roller coaster in their backyard. Doofenshmirtz tries to pull the East Coast to the west using tinfoil and a huge magnet.

Phineas and the gang introduce Ferb and Perry to their newest project - training domesticated squirrels to live in the wild. Meanwhile, Dr. Doofenshmirtz aims to do a better job of seeing through his evil plans now that Agent P is back.

Doofenshmirtz's latest "inactor" turns Danville citizens into contagious zombies. Agent P. and the gang try to save the town and avoid becoming zombies themselves.

The boys and Candace hatch a plot to reunite their mom and dad's favorite band for a wedding anniversary concert.

After taunting the boys for going to search for the "Lake Nose Monster", Candace begins freaking out on her lifeguard job, seeing the monster at every turn. Meanwhile, Dr. Doofenshmirtz tries to remove all the zinc from the lake, though even he's not sure why.

When Phineas and Ferb spin the house in order to paint it more quickly, Candace, inside the house, gets dizzy and collapses. She wakes up in the magical land of Odd and heads down the yellow sidewalk to Bustopolis to meet the Wizard.

Ferb and Phineas accidentally discover Perry's secret lair and are thrust into a spy mission of their own. Meanwhile, Candace travels on a tour bus with a girl band called "The Bettys"

Phineas and Ferb make the biggest ice cream maker for Isabella after her tonsils are taken out. Doofenshmirtz's daughter, Vanessa, spends the day at his lair and tries to convince his ex-wife that he's evil.

Based on the fact that a platypus doesn't do very much, Phineas and Ferb create a wooden toy version of Perry to sell to a toy company. Meanwhile, the real Perry heads off to stop Doofenshmirtz from building the Great Wall of the Tri-State Area and starting up toll booths at the only exits.

Phineas and Ferb create a monster truck for Candace to practice driving while Dr. Doofenshmirtz tries to find investors for his line of monster trucks that are actual monsters, with a trump card to take down the competition.

Candace plans a special birthday for Mom, and even a song, but Phineas and Ferb are always getting in her way of what she planned, unintentionally topping everything. Meanwhile, Doofenshmirtz creates a shrinking machine that will make whatever he hates implode.

Phineas and Ferb find a time machine at a museum and travel back to the Jurassic Age. Meanwhile, Perry is sad when Doofenshmirtz replaces him with a new nemesis, Peter the Panda, so he confides in a relationship talk-show host.

While on an archaeological dig, the boys discover a caveman who falls in love with Candace, who is dressed as a cave girl for costume party. Then, Phineas and Ferb assist Buford in locating his missing goldfish.

When Buford's goldfish goes missing, the boys help him find it out at sea. Meanwhile, Dr. Doofenshmirtz tries to destroy a tape of him 'saving' a kitten from a tree.

Phineas, Ferb, and Candace go to a Renaissance festival and Phineas and Ferb get Candace to go into a jousting tournament.

The guys decide to hold a competition between the girls to see which are better at sports. Also, the build a telescope in the backyard. Then, Jeremy's sister is tormenting Candace. Doofenshmirtz wants to be the winner of a dog show, and makes an attempt to liquefy a steak.