Ginny is a shy, cautious 17-year-old from New Jersey who prefers going unnoticed. She lacks travel experience and relies heavily on practical planning, as evidenced by her squeaky white sneakers. Her deceased aunt leaves her a set of rules and envelopes, prompting an unconventional European backpacking trip that forces Ginny out of her comfort zone.

Peg is an eccentric and spontaneous artist who died of a brain tumor three months before the story begins. Known for living an unconventional lifestyle in New York City, she frequently ran away when bored or stressed. She creates a complex travel game for Ginny, leaving a series of numbered envelopes designed to help her niece build confidence.

Richard is a practical, reliable man who works at the department store Harrods in London. His life is highly organized, reflected in his simply decorated home. He stands in sharp contrast to the eccentric artists Peg typically befriended, offering Ginny a stable, quiet environment during her time in England.

Keith is a theater student at Goldsmiths College in London who writes and directs his own productions. He possesses a rebellious streak, having acted out in his early teens before channeling his energy into the arts. Outgoing and lightly teasing, he provides a sharp contrast to Ginny's reserved nature.

Mari is an eccentric older painter living in Scotland. She has stars tattooed on her face like freckles and the names of deceased pets tattooed on her hands and feet. Living an unconventional life, she serves as a direct link to Aunt Peg's artistic past.

Miriam is Ginny's best friend from high school back in New Jersey. She represents Ginny's comfortable home life and provides a safe outlet for Ginny to express her frustrations, romantic developments, and sharp sense of humor via letters and internet messages.

Carrie is an Australian student spending her summer traveling through Europe with a group of friends. Easygoing and adventurous, she quickly welcomes Ginny into their group and invites her to travel with them to the Greek island of Corfu.

Knud is a Danish folk artist who lives on an ornately carved houseboat in Copenhagen. He studies and revives crafts using materials and processes that are over a thousand years old. Connected to Aunt Peg's past travels, he acts as a brief guide for Ginny in Denmark.

David is Keith's roommate at university in London. He experiences a difficult emotional period due to tension with his girlfriend over relocation plans, prompting Keith and Ginny to comfort him.

Fiona is David's girlfriend who plans to move to Spain. She exudes a cool confidence that initially intimidates Ginny during their brief introduction.

Alice is the proprietor of the Chinese restaurant located below Aunt Peg's former apartment. She remembers Peg fondly and hands Ginny the package of envelopes that initiates the European journey.

Beppe is a suave, older Roman man who helps Ginny avoid pickpockets. He takes her out for gelato and invites her back to his sister's apartment in the Trastevere neighborhood, presenting a charming exterior that quickly turns aggressive.

Mr. Knapp is an American tourist from Indiana traveling through Europe with his family. Dressed in practical, all-weather clothing, he is orderly and kind, offering to let Ginny share a room with his daughter when she cannot find a hostel.

Mrs. Knapp is an organized, efficient tourist from Indiana who leads her family on a rigorous tour of European landmarks. She manages all expenses and activities meticulously.

Olivia is the teenage daughter of the Knapp family. She is tall, quiet, and largely keeps to herself during her family's frantic sightseeing tours, though she eventually opens up to Ginny.

Phil is the college-aged son of the Knapp family. He follows along with his parents' heavily structured travel itinerary and accommodates Ginny's unexpected arrival.

Piet is a young museum guard in Amsterdam whom Ginny is instructed to find. He views Rembrandt's masterpieces simply as everyday objects in his workplace, a perspective that confuses Ginny.

Nigel is part of a group of four Australian students traveling through Europe. He is friendly and eager to include Ginny in their unstructured travel plans.

Emmett is an Australian student traveling with his brother Bennett and two friends. He helps convince Ginny to participate in a local karaoke contest.

Bennett is Emmett's brother and part of the tight-knit group of Australian travelers who accompany Ginny on the train and ferry ride down to Greece.

Paul is the owner of Les Petits Chiens, a uniquely decorated cafe in Paris. He fondly recalls the month Aunt Peg spent completely redecorating his business in exchange for room and board.

Michel is a somewhat surly vegetable seller who supplies produce to local chefs. Ginny is directed to him to find information about the cafe her aunt redecorated.