As the Griswold family sets off on their chaotic adventure across Western Europe, they find themselves in a series of unfortunate predicaments thanks to their victory on the wildly absurd game show Pig in a Poke. Their arrival in London is marked by a stay in a ramshackle hotel managed by a disheveled Cockney desk clerk, foreshadowing the chaos that lies ahead.
Clark's tendency to veer off the beaten path is evident as he drives on the wrong side of the road in their yellow Austin Maxi, propelling them into a wealth of misadventures. A nerve-wracking experience at the Lambeth Bridge roundabout ensnares them in a traffic jam, while a misguided detour at Stonehenge results in a comical disaster, toppling the ancient stones like dominoes.
When they reach the sparkling City of Light, Clark’s inability to communicate effectively in French leads to a cascade of humorous blunders, including the theft of their camcorder by a sly thief. Their attempts to snap a family photo at the Eiffel Tower take a strange turn when Rusty, played by Jason Lively, unwittingly attracts the attention of a group of young women, prompting Clark to intervene just as a mischievous dachshund mistakes their stenciled beret for a frisbee, sending it flying off the tower and into a fountain below.
Further mishaps ensue as they find themselves at a risqué can-can show, where Rusty unexpectedly gets involved with a certain lady of the night. Upon reaching West Germany, a mix-up sends them crashing into the home of an elderly couple, whom they mistakenly believe are relatives. Surprisingly, the couple welcomes them with open arms and treats them to a feast fit for royalty.
Attempting to merge into the local culture takes a wild turn when Clark transforms a lively Bavarian dance into a chaotic street brawl, his impulsiveness leading to him getting stuck in a narrow medieval archway while trying to extricate their Citroën DS from a precarious spot. As the Griswolds adventure spins wildly out of control, it's evident that their European journey is shaping up to be an epic comedy of errors.
Upon arriving in Rome, they unexpectedly find themselves caught up in a travel agency run by scheming thieves. The cunning leader poses as the manager while holding the real proprietor hostage. He hands the Griswolds a vehicle while slyly claiming he misplaced the trunk keys, leaving the family blissfully ignorant of the impending doom. The next day, Ellen faces shock as she discovers a billboard displaying intimate moments captured on their stolen camcorder, an act that leaves her infuriated with Clark, who had previously assured her that the footage was erased.
Searching for comfort at their hotel, Ellen encounters the very thief who rented them the car, unaware of his deceitful nature. Just as he attempts to snatch the car keys from her purse, chaos ensues as Clark chases the thief through the streets of Rome, culminating in a splashdown in a beautiful fountain after attempting to rescue Ellen from abduction. Ultimately, the police arrive to apprehend the criminal and restore safety.
As the Griswolds return home, the plane ride amplifies in chaos when Clark's search for a washroom triggers a series of misfortunes, sending the aircraft perilously low. Just as the tension peaks, Rusty triumphantly announces, "Yep, the Griswolds are back," as they catch sight of the Statue of Liberty's inverted torch, perfectly epitomizing their chaotic journey back from Rome.
