Atlantis

With a minimal amount of research, Ferb's found out that The Lost City of Atlantis is probably located right off the coast of Danville.

During a trip to the beach, Phineas, Ferb, Isabella, Buford, Baljeet and Irving try to find the lost city of Atlantis which is located in the bottom of the ocean. Then Candace and Linda enter a sandcastle building contest when Candace found out that Jeremy is the judge. Meanwhile, Doofenshmirtz creates an army of plants.

Episode Summary
The episode starts off with Candace looking for some peace and quiet on the beach. Unfortunately, Phineas, Ferb, Isabella, Buford, Baljeet and Irving are with her and Linda. Linda points out that there is a sandcastle contest on the other side of the beach. Linda tells Candace to join up but she replies saying the Phineas and Ferb would build a skyscraper or something huge so she won't compete. Phineas joins in the conversation saying that they'll all be finding Atlantis, which was probably off the coast of Danville.

Perry walks up to a man playing a guitar (a variation of Perry's theme tune) and Perry jumps into the guitar case. He falls into his chair where Carl greets him, pretending to be Major Monogram. Carl tells Perry half of his mission when Major Monogram appears and takes over. He concludes the mission and Perry flies off to where Heinz Doofenshmirtz is.

The kids are in scuba diving gear and Phineas tells Linda that they're going to find Atlantis. Linda says that they have such active imagination. Candace realizes the group leaving the beach means that they won't participate in the sandcastle competition. Candace grabs Linda and they both start building a sand castle.

Meanwhile, Doofenshmirtz is in his blimp when Perry climbs through the window and lands in a sack labeled Fertilizer. Doofenshmirtz is watering some plants whilst telling Perry what he is about to do. He has invented a growth formula to make the plants evil and help him take over the Tri-State Area.

The group are underwater and trying to find Atlantis when Irving decides to take photos. Once he has finished taking a picture, an eel steals his camera. Irving complains but Phineas tells him to use his other camera; his mind. Irving tries it whilst Isabella finds a seahorse. Baljeet says she can earn a patch and Isabella says that she was being sarcastic; seahorses aren't big enough to ride. Phineas finds a door with ancient inscriptions telling him how to open the door. He starts to read it when Buford decides it would be easier to punch the door. A huge rock separates, showing the lost city of Atlantis. The group explore Atlantis whilst singing a song about it. Once they have finished exploring, Phineas suggests bringing Atlantis above the water for everyone to see.

Back on the beach, Linda and Candace are still trying to make a sandcastle but fail for the third time. Jeremy walks over and explains he's the judge. He says he can't wait to see the Flynn-Fletcher sandcastle.

In the blimp, Doofenshmirtz starts spraying the plants with something that appears to be smoke. The plants come to life and start growing and turning evil. Doofenshmirtz's plan to attack Perry backfires on him badly with the plants attacking both him and Perry.

Candace and Linda start working very hard to get a good sandcastle but most of it collapses, again. Jeremy walks over and starts to judge their sandcastle when Atlantis floats up. It is being lifted by four weather balloons attached earlier by Phineas, Ferb, and friends. Candace is explaining about how their castle isn't perfect but they enjoyed making it when Jeremy gives them the first prize. He says he is going to get their blue ribbon and walks away. Atlantis sinks before Candace and Linda see it as they think Jeremy meant their half-collapsed castle. Linda tells Candace it must have been the way he feels for Candace that he gave them the blue ribbon.

In the blimp again, the plants take over the blimp and Perry escapes from his trap. He climbs out the window whilst Doofenshmirtz is calling for help. He returns a few seconds later with a chainsaw and starts cutting all of the plants. The spiked plants thrown overboard are what causes Atlantis to sink again.

Songs

 * Atlantis

End Credits
Doofenshmirtz thanks Perry but then gets an allergic reaction from the plants. Perry leaps out of the blimp with Doofenshmirtz cursing his immune system instead of cursing Perry as he usually does. The kids resurface only to find Atlantis has sunk and are upset. Ferb states that perhaps it likes to stay lost and Irving rejoices at having his pictures, until he realizes he had his thumb over his mental lens cap.

Whatcha doin'?
None.

Perry's entrance to his lair
Perry jumps inside a guitar case.

Evil Jingle
Doofenshmirtz Evil Incorporated! Instrumental

Background Information

 * This episode reveals that Candace was once good making sand castle and sculpture.
 * Doofenshmirtz calls Perry just for "Perry".

Production Information

 * At a run time of 9 minutes and 13 seconds counting the credits, this is the shortest episode made to date.

Errors

 * The Titanic is shown to have it's mast upright along with the steam poles and in one piece, but the mast should be lying on the bridge of the ship, the stern should be disconnected, and the smokestacks shouldn't be connected to the ship at all. Only the ship's hull is correct as it's unpainted as the water has washed the paint away.
 * The boys would have to go way deeper in the water than that to find the Titanic and the other underwater objects, including Atlantis.
 * When Carl removes the fake mustashe his eye lids turn to the color of his skin. Normally, they are the same color of his glasses lens.

Continuity

 * Irving appears for the third time in this episode (he apparently stowed away in the trunk when Linda stopped for gas).
 * Candace wears the same swimsuit from "De Plane! De Plane!".
 * Second time a bag of manure was used ("I, Brobot").
 * Ferb's, "Perhaps the lost city of Atlantis wanted to stay lost" echoes, Phineas's, "He must not want the world to know he really exists" ("The Lake Nose Monster").

Allusions

 * Atlantis is a mythical city from Greek mythology.
 * Baljeet's pose on the clam shell is the same as the painting The Birth of Venus.
 * Irving's ability to take pictures with the mind by saying "click" is that of Cam Jansen.
 * You can briefly hear the Titanic theme as Phineas, Ferb, Isabella, Buford, and Baljeet enter the water, the movie Titanic also seems to be a recurring theme in the show.
 * "Four corners of Atlantis" may refer to the saying "four corners of the world".
 * The musician said "Thank you. Thank you very much" in the style of Elvis.
 * Spongebob SquarePants - During the song Atlantis, Ferb is shown drinking tea from his helmet, like Spongebob and Patrick do in the episode "Tea at the Treedome".
 * Frank Lloyd Wright was a famous architect. Candace's comment that she was "Frank Lloyd Wrong" is a pun on his name.

Cast

 * Vincent Martella as Phineas
 * Ashley Tisdale as Candace
 * Thomas Sangster as Ferb
 * Alyson Stoner as Isabella
 * Caroline Rhea as Mom
 * Mitchel Musso as Jeremy
 * Dan Povenmire as Dr. Doofenshmirtz
 * Jeff "Swampy" Marsh as Major Monogram
 * Richard O'Brien as Dad
 * Dee Bradley Baker as Perry
 * Jack McBrayer as Irving
 * Tyler Mann as Carl