When Principal Skinner makes a fool of himself on a freeway, Milhouse manages to catch the scene on his phone. He calls most of his friends to see Skinner getting beaten up by a drunken-(as-always) Barney, but cannot call Bart. When Nelson asks why, Milhouse explains that Bart does not have a cell phone. Bart is taunted for missing out on laughing at Skinner. Bart asks Marge for a phone; Marge explains that, because Mr. Burns has cut Homer's pay, she cannot afford it (or a dream trip for Lisa to Machu Picchu). A depressed Bart takes a walk past the Springfield Glen Country Club, and is hit by a golf ball. He angrily runs onto the golf course to find who hit him, and finds it was Dr. Julius Hibbert. Hibbert pays Bart a dollar for the ball. Bart realizes he can earn enough money for a cell phone by retrieving golf balls.
Bart's glee is cut short when Groundskeeper Willie accuses Bart of cutting in on his job, and confiscates all the golf balls. Nearby, a celebrity golf tournament is underway. Celebrity Denis Leary (guest starring as himself) prepares to swing, but misses when his cell phone rings at the same time. Leary throws away his phone, which lands beside Bart. While going to inform Milhouse of his new cell, Bart receives a call from producer Brian Grazer (also guest starring as himself), who asks Leary to star in the film adaption of Everyone Poops. Bart, realizing the phone belongs to Leary, pretends to be him.
A mischievous Bart makes prank calls to bartenders all over the world, and has all of Boston native Leary's money spent on New York Yankees hats and uniforms. Marge overhears Bart and Milhouse's mischievousness, and when Milhouse confesses that it belongs to Leary, confiscates Bart's phone. Leary calls his cell, and Marge answers, apologizing for her son's behavior. Leary, still angry with Bart's tricks, suggests Marge activate the GPS on the phone and return it to Bart, allowing her to track down Bart's every move. He says that this is how he tracked rival actors who "stole" film roles he wanted.
Somewhat guiltily, Marge activates the GPS and returns the phone to Bart. Marge is able to prevent Bart from watching an R-rated movie, gambling at a horse race, and skating down steps and hurting himself. Bart realize that as long as Marge and Homer have him under constant surveillance, he cannot have any fun. Lisa is shocked by Marge's injustice and confronts her for it. When Marge refuses to acknowledge she is abusing Bart's privacy, Lisa decides to tell Bart what is going on. Bart decides to get revenge. He ties the GPS chip to the leg of a scarlet tanager, which flies away. Marge, thinking the bird is Bart, assumes that Bart is running away from home. While Homer, Lisa, Marge, and Maggie conduct a nationwide search for Bart, Lisa realizes that the bird is what they had been chasing. After checking research on her laptop, she discovers the bird is migrating to Machu Picchu, her dream trip they could not afford. Knowing this, Lisa deliberately lets the bird go free so the family can chase it to Machu Picchu.
Bart relishes his newfound freedom during the daytime, but quickly becomes frightened of being alone at night. When the Simpsons arrive in Machu Picchu, they continue the search for Bart. Marge, despite being exhausted, swears to be more over-parenting with Bart, but Lisa convinces her to rest on an ancient sculpture, below the statue of the ancient Peruvian God of the Sky. Marge quickly falls asleep, and is instantaneously pulled into a dream world where the God of the Sky shows her ancient Peru. He teaches her how throughout history, parents who over-parented their children could never set them free, which was how they were conquered by the Conquistadors and Inca renegades (although historically Machu Pichu was never actually discovered or conquered by the Conquistadors). Upon waking, Marge learns that she must let Bart take steps for himself. Homer discovers that the family has been following a bird the whole time, assuring Marge she knows exactly where Bart is. Upon returning to Springfield, Marge asks Bart if he missed her. Bart says he did not notice they were gone (for two weeks), so Marge, depressed, goes upstairs. However, upon reaching the stairs, she is stopped by Bart, who quickly begs her to never leave again. The episode ends with Lisa asking Homer, "Where's Maggie?" As it turns out, the family had left her in Machu Picchu, where she is being worshipped.