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

After Doofenshmirtz is defeated, a new threat in the 2nd Dimension emerges, leaving it up to Phineas, Ferb, Candace and her resistance fighters to defeat this new foe.

It's been 10 years after the events of the present, and Phineas must decide what university to go to. After discovering that Isabella had a crush on him for years, Phineas must reach her before she leaves for college and express his true feelings for her. Meanwhile, Doofenshmirtz has a mid-life crisis.

It's the last day of summer vacation and Phineas and Ferb decide to seize the day and make the most of it. Unfortunately for Candace this means it's also her last chance to bust her brothers... or is it?

When Phineas and Ferb discover a commemorative coin from the 1903 Danville World’s Fair, Lawrence recounts the events of the festival to them, in which steam-driven devices were introduced and a set of kids, who were very much like them, were preparing for the highly anticipated event.

When Candace is accidentally zapped by Doofenshmirtz’s Stinkelkrampen-Inator (aka Good Luck-Inator), she realizes she has a good chance of busting Phineas and Ferb.

Candace brings her plush Ducky to life. Doofenshmirtz encounters a Giant Floating Baby Head. Phineas, Ferb, and their friends confront a horde of evil platypuses.

Candace thinks she can trap the boys at last when they ask her to call Mom if they get stuck in their giant Gordian Knot, but is distracted by helping Jeremy open his mini-safe.

Phineas and the gang celebrate Isabella's birthday in a big way, but all she really wants is some quiet time with Phineas. Meanwhile, Doofenshmirtz has installed his Bugs Me-Inator onto an evil bug bus and is driving around Danville turning all the things that bug him literally into bugs.

After studying hours of horror movies, Doofenshmirtz develops a theory that enlarging small, cute animals into giant beasts will help him take over the Tri-State area. But when he puts his plan into action, he soon realizes it might be too much for him to handle. Meanwhile, Phineas and Ferb make a giant revolving foam city so they can safely perform skateboarding tricks, and Candace's tour of the Danville Space Laboratory gives her an opportunity for a high-tech bust.

National Hockey League star Luc Robitaille offers his assistance when Phineas and Ferb take an ice hockey game to the extreme. Meanwhile, Doofenshmirtz build an Abominable-inator to make himself bigger, scarier and hairer.

Dr. Doofenshmirtz and Major Monogram have their hearts set on revealing the top 10 musical numbers from Seasons 2 and 3, but soon find out that celebrity host Kelly Osbourne has been brought in to fill the role. Unwilling to submit to playing second fiddle, Doofenshmirtz makes it his mission to thwart Kelly until Perry the Platypus sets out to stop his nemesis from ruining the entire show. Maia Mitchell ("Teen Beach Movie") also guest stars.

Phineas and Ferb build a wall for climbing. Candace is recording a Fireside Girls book with Irving and loses her voice. Meanwhile, Dr. Doofenshmirtz creates the Just-Desserts-inator.

When Linda becomes overwhelmed for organizing a block party, she asks Phineas and Ferb for help. Norm falls in love with Rodney's female robot.

Candace and Stacy compete in Phineas and Ferb’s Ultimate Obstacle Course. Doofenshmirtz plans to humiliate his brother, the Mayor.

Phineas and Ferb deejay at Vanessa's Halloween party. Doofenshmirtz hunts for hidden treasure in a castle.

When Candace is stumped about what to get Jeremy for his birthday, she reluctantly asks Phineas and Ferb for their help in creating the ultimate gift. Meanwhile, Doofenshmirtz plans to make fears a reality with his Worst-Fear-Inator, but his plans backfire when he finds himself battling his own fears instead.

Buford removes a part from a tire swing the boys are building and it accidentally shoots a ray that turns Candace into a fly. Meanwhile, Doofenshmirtz is suffering from evil scientist’s block.

Candace challenges Buford to keep Phineas and Ferb’s invention from disappearing so that she can sweep in and casually bust her brothers. Across town, Doofenshmirtz has had one too many lattes and is experiencing an extra burst of evil energy.

The boys make a giant inflatable wading pool for Mom. Candace reveals her "Emo" side. Doofenshmirtz attempts to become ruler of all bees.

When Pinky goes missing, Phineas & Ferb create a machine that will amplify Buford’s senses to those of a dog’s. However, it works so well that the animal agents’ secret identities are put in jeopardy. Meanwhile, Candace tries to meet up with Jeremy for lunch at City Hall but gets stuck in a mandatory tour.

The gang switches bodies with alien tourists for a free intergalactic vacation.

Inspired by Candace's book club selection, The Iliad, the boys reenact the Trojan War -- but with a Phineas and Ferb twist. Meanwhile, Perry discovers that Doofenshmirtz has a major problem with throwing things away so he helps him find his De-Clutter-Inator.

Phineas and Ferb plan their own New Year's Eve ball drop, complete with a customized multi-dimensional ball, while Candace makes it her resolution to refrain from busting her brothers before the clock hits midnight. Meanwhile, Doofenshmirtz uses a Resolution-Changer-inator in his tie as he continues the never-ending attempts to take over the Tri-State Area.

The gang switches bodies with alien tourists for a free intergalactic vacation.