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.
Candace wakes up to find Buford already in the Flynn-Fletcher backyard. She asks why he's there so early, and he explains that a Van Stomm must show up, anyway, if they set their alarm clock too early. After he criticizes Candace's lack of busting skills, she challenges him to keep the boys' invention from disappearing, and he accepts due to another Van Stomm rule.
Major Monogram wakes up Perry, who is sleeping on Phineas' bed, from a Stumbleberry Finkbat trading card, explaining that Carl had installed a nanoscreen on it while disguised as Candace. Monogram explains that Dr. Doofenshmirtz was seen ordering an extra-large coffee, and sends Perry out to stop him just as Phineas and Ferb walk in.
As Linda leaves for the beach, Candace states that she won't need to call to bust the boys, as she's got everything covered. Perry flies to Doofenshmirtz Evil Incorporated, where Doofenshmirtz, hopped up on evil energy due to his soy venti latte extra-caf-and-a-half quadruple sugar, blood pressure bomberino, traps him in a cage via a contraption inspired by a board game. He then presents his Luffa-plex Dill Pickle-inator, which sends people into orbit. Perry simply steps out of the cage and begins fighting Doofenshmirtz.
Back at the Flynn-Fletcher backyard, Phineas and Ferb are surprised to see Buford there so early. Baljeet, Isabella, and Irving arrive, and Phineas presents his idea for the day's project: a tooth-shaped, dental hygiene-inspired theme park ride, inspired when the boys were brushing their teeth. Their friends all agree to help out, with Irving selling tooth-shaped balloons, or "Toothaloons." While everyone builds the Dental Hygienosphere, Candace keeps an eye on Buford, confirming that he's making sure it doesn't go anywhere. Phineas, Isabella, Ferb, and Baljeet climb aboard for the ride, but Candace pulls Buford off.
At D.E.I., Perry knocks Doofenshmirtz down the contraption's stairs. He then jumps to the top of a boxing glove with an anvil under it. Doofenshmirtz attempts to follow, but is launched directly into the anvil, which promptly falls on him. While Candace lists all sorts of things that could happen to the ride, making it disappear, Buford points out that he has prepared for all of these. Candace gleefully runs off to get Linda.
Meanwhile, Perry and Doofenshmirtz are still fighting, and Perry kicks Doofenshmirtz into the -inator, which starts firing. The ray hits a chair by Buford, who realizes he didn't take into account random green rays from the sky, and begins throwing objects such as Irving's Toothaloon helium tank into the ray's path so they won't hit the ride. When he's run out of objects, he jumps into the ray's path and starts floating towards space. However, his Tuff Shoo Lay Sizz catch on the ride, yanking it away just after the four kids exit.
Doofenshmirtz attempts to use fake martial arts to fight Perry, but accidentally kicks his shoe at him, stunning him. Doof runs to the -inator and attempts to send Perry into orbit, but Perry throws the shoe at him, causing the ray to hit the top of the Doofenshmirtz Evil Incorporated building instead, taking Doof and Perry with it. Buford, still floating, detaches the giant tooth from his shoelaces, and the ride falls to earth. However, Perry breaks the -inator with Doofenshmirtz's shoe, causing all the floating objects, Buford included, to fall. Fortunately, his Tuff Shoo Lay Sizz catch on the tree in the Flynn-Fletcher backyard, and Phineas greets him.
Candace brings Linda into the backyard to try and bust the boys, but the ride is nowhere in sight. Linda offers pie, and everyone except Buford (who is still stuck in the tree) runs inside. Candace orders Buford to explain himself, and Buford musically states that when a Van Stomm doesn't succeed the first time, they give up. Somewhere in the desert, the top of D.E.I. crashes down. Doofenshmirtz climbs out and states that he's okay, just as the Dental Hygienosphere lands on him, crushing the building. He immediately states that he is no longer okay.