Thaddeus and Thor / De Plane! De Plane!

The Flynn-Fletcher’s neighbors have relatives visiting who bear an uncanny resemblance to Candace, Phineas, and Ferb. In fact, older sister Mandy has two younger brothers, Thaddeus and Thor, who drive her crazy with their ambitious projects. Although Candace and Mandy initially bond, they soon compete, urging their brothers to build the best backyard fort. Meanwhile, Perry finds himself in the middle of Dr. Doofenshmirtz’s family reunion where Dr. Doofenshmirtz tries to win the annual kickball tournament with the Kick-inator 5000. Phineas and Ferb set out to build a bigger plane than Howard Hughes’ wooden Spruce Goose, so they build it out of papier-mâché, to do a similar theme to the Spruce Goose, complete with in-flight service and entertainment. Dr. Doofenshmirtz is doing his part to be green by using recycled materials to build an “Evaporator-inator” to dry up all the pools in the Tri-State Area. Meanwhile, Candace and Stacy attend Jeremy’s pool party only to discover an adventurous Australian girl is capturing Jeremy’s attention.

Summary
"Your brothers are annoying you, too?"

- Mandy

Linda tells Candace that she’ll be going out to buy some groceries. Candace overreacts and asks her if she’s in charge of Phineas and Ferb, whereas Linda replies yes. Candace walks out into their backyard and tells Phineas and Ferb not to build anything today.

Candace walks away and spots Mandy, a visiting relative of Mrs. Weaver, the Flynn-Fletchers’ neighbor. Mandy tells Candace about her brothers, Thaddeus and Thor, who constantly annoy her with their inventions, while Candace talks to her about Phineas and Ferb. The two soon argue about whose brothers are even more annoying.

Thaddeus and Thor enter Phineas and Ferb’s backyard and tell them that where they come from, they’re known as “the best.” Thaddeus tells Phineas and Ferb that they’ll be building a backyard fort, and says to Thor who they’re going to outdo today.

Candace finds out about Thaddeus and Thor’s competition and tries to get Phineas and Ferb to build a backyard fort that’s even greater than Thaddeus and Thor’s so as to prove to Mandy that Phineas and Ferb really are better than Thaddeus and Thor.

Meanwhile, Perry enters his lair and Major Monogram informs him that Dr. Doofenshmirtz has been sighted at Danville Park.

Perry rushes over there and sees Dr. Doofenshmirtz at his family reunion. Dr. Doofenshmirtz tells Perry about a time in his life when his mother’s love was inexplicably linked to kickball, and his brother Roger always outshone him.

Dr. Doofenshmirtz shows Perry his new invention, the Kick-inator 5000. He tries to get test it out with Perry but tells him it’s in process when it accidentally kicks him in the face. He tries everything from adjusting the position of the ball to swinging it on a string. Finally, after many attempts, he kicks the ball.

Candace realizes that Linda has arrived in the driveway. She tells her mom that she forgot “that stuff,” causing her to drive back to the grocery store while Candace is left to deal with the competition. Thaddeus and Thor reveal their fort, which has a slide and licorice dispenser.

Candace reveals Phineas and Ferb’s fort, which turns out to look just like a regular fort. Candace feels disappointed and walks out. However, Ferb presses a button and their real fort grows out of the ground, which turns out to be nearly fifty feet tall, complete with a bowling alley and a swimming pool. Thaddeus and Thor look impressed as Phineas and Ferb outshine them.

Meanwhile, Dr. Doofenshmirtz kicks the ball so far, it bounces off Phineas and Ferb’s fort. As Heinz stands feet from home, gloating to his brother Roger, the ball comes back. Roger catches it and tags Dr. Doofenshmirtz out, which impresses their mother and leaves Heinz sitting in the dirt to be comforted by Perry.

Mandy leaves with Thaddeus and Thor in embarrassment. She tells Candace that Phineas and Ferb are really the best, and Candace goes outside to see their real fort. Ferb deactivates the fort (due to zoning regulations) and it sinks right into the ground just as Candace and Linda arrive outside. Linda, who can only see the ordinary fort level, says that it’s “great that they’ve started to take an interest in building things.” Candace faints.

"Eat your heart out, Howard Hughes!"

- Phineas Flynn

The episode starts off in Candace’s room when she and Stacy were deciding on what to wear for Jeremy’s pool party. Candace was asking Stacy which swimsuit to wear. After explaining why Candace’s swimsuit choices were not good, Stacy then tells Candace to let her conscience do the talking and go with the swimsuit that she touched first. After Candace thanked the fashion-phenom, Stacy then asked her for advice of what hat to wear to the party. Candace responded by saying that it doesn’t matter. After looking at the hats for a few seconds, Stacy agrees with Candace and says that she fusses too much.

Meanwhile in the Flynn-Fletcher living room, Phineas and Ferb are watching an informational TV show, where it tells about Howard Hughes’ Spruce Goose, which is the largest plane ever built. Phineas decides to break the world record and tells Ferb he knows what he’s going to do today.

Phineas and Ferb go out to their backyard with stacks of newspapers. Isabella, the Fireside Girls, Buford, and Baljeet come over and offer them some help. Phineas tells them that Howard Hughes named his plane the Spruce Goose because it was built out of wood, and since their airplane will be built out of paper-mache, they decide to name it the Paper Pelican.

Meanwhile, Perry enters his lair. Major Monogram informs him that Dr. Heinz Doofenshmirtz has gone green, but still is doing something neutral. Perry arrives at Dr. Doofenshmirtz’s building. Dr. Doofenshmirtz pretends to pick up the phone but traps Perry in it. He shows Perry that he has created an Evaporator-inator out of recycled materials. He flashes back to a time when his mother would never let him swim in public pools.

Candace and Stacy arrive at Jeremy’s pool party, where they see him talking to a blond girl with an Australian accent, whom Jeremy calls Nicolette. This worries Candace deeply. Phineas realizes that they have built the biggest airplane ever. Phineas, Ferb, and their friends enter the airplane. They ignite the airplane, while Isabella and Baljeet serve refreshments to Buford and the Fireside Girls as flight attendants. After Buford voices a complaint about what he is served, Baljeet creates a dish called Peanut Chicken with the motto “So peanutty, you won’t even taste the chicken.” It gets Buford’s grudging approval.

Stacy helps Candace and tells her that she’s much cooler than Nicolette. Candace clears her throat angrily and argues with Nicolette. Meanwhile, Dr. Doofenshmirtz activates his Evaporator-inator just as Candace is about to show everyone a real dive. Everyone grabs their skateboards and use the swimming pool as a skate park. Meanwhile, Perry fights with Dr. Doofenshmirtz. Dr. Doofenshmirtz is about to evaporate Perry with his Evaporator-inator, but Phineas and Ferb’s Paper Pelican passes over the sun and causes the Evaporator-inator to lose its power, giving Perry a chance to defeat Dr. Doofenshmirtz.

Jeremy accidentally slips and his skateboard lands near the diving board. Candace walks off and gets caught on the skateboard, causing her to skate everywhere. Jeremy becomes impressed by Candace’s skill. Phineas and Ferb’s Paper Pelican passes over the sun just as Candace crashes into Jeremy. Phineas and Ferb land their airplane in a body of water, where Baljeet explains that since the airplane is made of paper-mache, it’ll soak into the water. Then they all float to land.

Cast

 * Vincent Martella as Phineas
 * Ashley Tisdale as Candace
 * Thomas Sangster as Ferb
 * Alyson Stoner as Isabella
 * Maulik Pancholy as Baljeet
 * Isabella Acres as Katie
 * Caroline Rhea as Mom
 * Mitchel Musso as Jeremy
 * Ariel Winter as Gretchen
 * Kelly Hu as Stacy Hirano
 * Dan Povenmire as Dr. Doofenshmirtz
 * Jeff “Swampy” Marsh as Major Monogram
 * Richard O'Brien as Dad
 * Dee Bradley Baker as Perry
 * Bobby Gaylor as Buford
 * Shae Brewster as Nicolette
 * Cloris Leachman as Heinz Doofenshmirtz’s mother