Anna Foster, played by Mandy Moore, is the spirited daughter of President James Foster, portrayed by Mark Harmon. After a disastrous first date thanks to overbearing Secret Service agents, Anna insists on having more freedom. The President agrees to limit her security detail to just two agents for his upcoming trip to Prague. Known by her Secret Service codename, Liberty, Anna is thrilled at the thought of some independence. In Prague, while attending a concert with her friend Gabrielle La Clare, Anna notices the watchful eyes of numerous agents, leading her to believe her father has gone back on his word.
With Gabrielle's help, Anna decides to escape her protectors. Outside the theater, she meets Ben Calder, played by Matthew Goode, asking for a motorcycle ride, unaware that he, too, is one of her guardians. Ben soon alerts his fellow agents, Alan Weiss and Cynthia Morales, about her whereabouts, all while President Foster insists that Ben should protect her without revealing his identity, allowing Anna to feel a sense of freedom while ensuring her safety.
Feeling liberated, Anna jumps into the Vltava River, mistaking it for the Danube, and later climbs a rooftop with Ben to enjoy an opera performance in a plaza. The following morning, her carefree antics cause alarm for her father when he sees compromising photos of her, prompting him to confront her about her recklessness. Despite his anger, Anna decides to attend the Love Parade in Berlin and, with Ben's reluctant compliance, they board a train that unexpectedly heads to Venice instead.
In Venice, their escapades continue as they meet the whimsical Scotty McGruff, who inspires them to spread joy with Six Million Dollar Man stickers. However, trouble arises when Anna realizes her wallet is missing, stolen by McGruff. The duo takes cover from curiosity seekers and shares a gondola ride with a kind gondolier, Eugenio. To evade their pursuers, Ben kisses Anna, pretending they are newlyweds. When Eugenio offers them shelter, Anna misunderstands Ben's feelings, attempting to get closer, only to be rejected yet again.
As they traverse through the Austrian countryside after a misunderstanding, Anna's impulsiveness leads her to a bungee jumping event. Just as she is about to jump, Ben insists on joining her, showcasing his growing affection. Later that night, amidst playful flirtations and confessions of feelings, Anna is hurt when she discovers Ben's secret identity as a Secret Service agent. Enraged, she distanced herself, only to find herself in danger from a group of men. Ben comes to her rescue, and they ultimately return to the safety of the United States.
Back home, as Anna prepares for college, she shares with her mother her melancholy over her broken heart. With her protectors still by her side, Anna is reminded of her European adventure by the sight of a Six Million Dollar Man sticker. During a college exchange in London, her father reveals that Ben has left the Secret Service to pursue photography. This leads Anna to finding him during an opera performance, where they share a kiss, rekindle their romance, and escape on his motorcycle, with their former guardians trailing behind.
