Two single parents join forces when their children run away from a French boarding school.

Eleven-year-old American Danny Andrews is running away from his exclusive Swiss boarding school to reunite with his father, when ten-year-old Janine Duval, a French student at the school who harbors a crush on Danny, begs him to take her along. After crossing the nearby French border that night, the children talk about their parents. Danny's father Mike is a widowed American businessman who works in Paris, while Janine's mother Suzanne is a divorcée who rarely visits her daughter. Back in Paris, an exasperated Mike is supervising the "inefficient" French workers who are renovating his new business operation when the boarding school calls to tell him his son has run away. Arriving at the school later that day, Mike insists that he has given his son all the possible "advantages" and cannot understand why the normally well-behaved child felt the need to leave. Suzanne, who is also there, assumes Danny forced her daughter to leave and blames Mike for their disappearance. Danny's roommate, David, Earl of Bardingham, explains to the parents that Danny ran away to prove his self-sufficiency to his father in hope of being able to stay with him in Paris, while Janine's motivations were purely romantic. Although the French police are looking for the children, Mike and Suzanne decide to rent a car and follow the only route to Paris. When they discover the last car in the village has been rented, they accept a ride from a concerned father, whose small car becomes crammed after he picks up several other passengers, forcing Suzanne to sit on Mike's lap during the bumpy ride. Meanwhile, Danny and Janine are miles ahead of their parents when Janine realizes she has left their food in the truck from which they hitched a ride. She laments that she is only a hindrance to him, but Danny insists that he cares more for her company than for food. Soon after, they meet a group of peasant children picnicking with their parents. Upon hearing the runaways' story, the children devise a plan to help them. Distracting their parents, the children steal food for the pair, then hide them in the back of their parents' truck while they travel to the next town. Some miles behind, Suzanne and Mike finally reach the next town only to find the police station is closed for lunch and there is not car rental available, after which Mike launches into a tirade about French customs. Frustrated by the American's brash and patronizing behavior, Suzanne advises Mike to remember his manners. Accepting a French motorcycle officer's offer to drive them to the next town, the three begin a reckless journey, narrowly escaping several crashes on the small motorbike. On the peasant's truck, the children create a diversion enabling one boy to call his cousins and prepare them for the arrival of the runaway pair. When the truck arrives in the next town, the cousins start a brawl, confusing the police, who are checking vehicles for the missing children. After Danny and Janine are guided by the village children through a fair, another boy and girl with a similar description to the missing pair exchange clothes with Danny and Janine and engage the police in a chase while Danny and Janine board a river barge, where Danny cuts Janine's long blonde hair to keep them from being recognized. Later that night at a hotel, the parents realize that despite their good intentions, the school was actually providing them with an escape from parenting and was not the best choice for the children. When Mike apologizes for his hot temper, Suzanne admits she has been selfishly anxious to return to her fiancé in Monte Carlo, whom she is to marry in two days. The next morning, Mike offers to continue the chase alone; however, when Suzanne receives a call from Monte Carlo, she decides to proceed on the journey with Mike instead. Now on a scooter, Mike and Suzanne find the road is blocked for NATO training maneuvers and appeal to the commanding officer, General Medworth. The befuddled officer assigns hundreds of men to scour the area; however, Danny and Janine are already at the camp enjoying tea and cakes with an enlisted man, who is oblivious to Medworth's orders. While dozens of tanks haphazardly crisscross the countryside, the children easily escape the area on the back of a military jeep, once more outwitting the adults. Later that afternoon, Danny and Janine are lost in a forest when they encounter a deaf, mute hermit who happily gives them dinner and lodgings for the night. Meanwhile, Suzanne and Mike decide to look for the children on their own, but the inept soldiers lock them up, assuming they are the lost "American boy" and "French girl." When Mike asks an American soldier to place a call to his business for him, the soldier suggests that Americans are overworked and should take a hint from the French leisurely approach to life. The next morning, the hermit shows the children the way to the next town, where an international bicycle race to Paris is about to begin. When the youngsters spot the American newsreel car, they claim to be one of the cyclists' children, ensuring them a ride to Paris. The next day, after Suzanne and Mike are released, they see a picture of the children alongside a bicycle rider in the newspaper and track down the newsreel reporter, but the children are already gone. After visiting dozens of police stations in Paris, Suzanne and Mike return to his apartment, where they find the children fast asleep. When Mike receives a call to return to work that day, he announces that he is taking a long weekend off. Both parents agree that their children will remain with them from now on.