Ferris Bueller is now a security guard, working the night shift at a history museum. One night, his boss calls him and he's like "Bueller, I need you to work one hour longer tonight. And make sure nobody steals the Diamond of Hope, because the Vice President of Egypt is coming in tomorrow to check it out." One hour longer? You think Ferris Bueller is going to stand for that? Hell no, he's taking the night off. Ferris sets up a tape recorder and a mannequin in a security guard outfit at the front desk, then gets ready to hit the town. On the way out, he calls his buddy Cameron. Ferris is like "Hey man, we need to borrow your dad's car again." Cameron's like "Ferris, it's 1:30 AM, what the fuck? We're 45 years old. We have our own cars." Ferris says to the camera, "Cameron is so tight, that if you stuck the Diamond of Hope up his ass, the Vice President of Egypt would be happy because it'd just make the Diamond more valuable." Cameron's like "What? That doesn't even make sense. Now stop calling me, I have to take my daughter to ballet practice in the morning." Ferris is like "See you in 10 minutes", and hangs up the phone. Meanwhile, Ed Rooney has been watching all this from the bushes and taking notes. He doesn't have any reason to be following Ferris, he's just a crazy old lunatic.
Cameron is getting dressed to go out with Ferris. Mrs. Cameron isn't too happy about this, because she thinks Ferris is a bad influence on him, but Cameron promises he'll only be gone for like half an hour. Boy, is he wrong. Dead wrong. Cameron goes outside, and Ferris is already in his car. He's like "Hey man, I just hot-wired your dad's Ferrari!" Cameron's like "That's my Ferrari! I saved my money for 20 years to buy it!" Ferris says to the camera, "Cameron is so fucking tight, that if he ate the Diamond of Hope, he'd shit out 25 mini-Diamonds of Hope, and personally save Egypt's economy. The Vice President of Egypt would make him an honorary Egyptian." Cameron's like "I'm not that tight. Who are you even talking to?" Meanwhile, Crazy Ed Rooney is still watching from the bushes. He makes a phone call to Ferris's Sister and tells her that her brother isn't really sick at all, he's just skipping work. She threatens to call the police if he ever calls her again, and hangs up on him. Rooney cries.
Ferris and Cameron are driving to the city in Cameron's Ferrari. That "BOMP BOMP chick-chicka" song is playing. Ferris is like, "Here's the plan, we're gonna call my girlfriend, Sloane Peterson, and you're gonna pretend to be her dad so we can get her out of work." Cameron gets all serious and he's like, "Dude... Sloane died of a drug overdose 12 years ago." Ferris looks at the camera and says, "Cameron is so motherfucking tight, that if the Vice President of Egypt stuck his hand up his ass to search for the Diamond of Hope, his Egyptian hand would get stuck in there and they'd have to amputate it. Then the Vice President of Egypt would only have one hand." Cameron is speechless. Ferris stops the car outside a strip club, and gives Cameron his phone. "This is where she works. Now call her up and pretend to be George Peterson." Also, Ed Rooney has strapped himself to the bottom of the car like in Cape Fear or whatever. But the car went ever a speed bump on the way to the strip club and knocked Rooney unconscious. He might have brain damage.
Meanwhile, back at the museum, a pair of masked diamond thieves are about to break in by cutting a hole in the glass. But when they try to cut into it with their special laser, it sets off Ferris's tape recorder/mannequin contraption, and the mannequin points a flashlight at the thieves and says "Who goes there?" Then the tape rewinds itself because that's the only phrase Ferris recorded. The thieves are like "Holy shit, the Vice President of Egypt can keep his stupid diamond! Let's get outta here!" and they run away.
Cameron calls the strip club and tells the manager that he wants to speak to his daughter, Sloane. The manager's like "Okay, she gets off stage in 5 minutes." 5 minutes later, Sloane picks up the phone, all "Daddy, is it really you?" It isn't the real Sloane, it's a stripper who happens to be named Sloane. Her father abandoned her when she was 8 years old, and she's been waiting for this phone call ever since. But Cameron isn't really her father, and when she comes outside and sees Ferris sitting there, she's like "You again? I told you to leave me the fuck alone!" A bouncer comes out of the club and he's like "Is there a problem here?" and Sloane tells him that these two cocksuckers are harassing her, so the bouncer grabs Cameron and punches him several times in the face. He then kicks Ferris in the chest, breaking two of his ribs, and makes him bite the curb. Just then, Ed Rooney jumps out of the shadows and points a gun at the bouncer. He's like "Let him go, motherfucker. This one's mine..."
Later, Ferris and Cameron are being driven home by Rooney in the Ferrari. Ferris is like "Thanks for your help back there, Mr. Rooney. You saved both our asses." Rooney's like "Speaking of asses, Cameron is so tight, that if we were in the Bizarro Universe and you shoved the Diamond of Hope up his ass, the diamond would turn into coal, because we're in the Bizarro Universe and things are backwards." Ferris smiles, "Yeah, I said the same thing earlier! You're alright, Rooney. You're alright." Ferris and Rooney both laugh, while Cameron cries in the back seat. After Ferris & Rooney drop Cameron off at home, Cameron packs up all of his family's shit so they can movie far away from this town. Ferris & Rooney steal Cameron's Ferrari, but Cameron doesn't say anything, he just wants to get rid of them. Ferris gets back to the museum just before the Vice President of Egypt shows up to view the Diamond of Hope. He and Rooney shake hands, then Rooney walks into the bushes and fades away, his work here is done. Ferris puts his security guard uniform back on and sits down at the front desk. He smiles at the camera, then coughs up some blood because he got the shit kicked out him a few hours ago and is still bleeding internally. Chick-chickaaa.