The 13-year-old eldest child of the Melendy family, Mona is a fair-haired girl with thick braids that she often threatens to cut off. She aspires to be a theater actress, rehearsing parts in the bathroom and covering her walls with photographs of famous performers. She balances her maternal nature toward her younger siblings with a developing desire for independence and a more grown-up identity.

A 12-year-old boy with mussy hair and a mischievous spirit. Rush is a talented piano player who frequently practices in the family's attic playroom and hopes to design machinery in the future. Though he sometimes displays arrogance or teases his sisters, he is fundamentally kind-hearted and quick to admit his mistakes.

A 10-year-old girl with dark, curly hair, Randy is highly creative and imaginative. She dreams of becoming a dancer and a professional painter, frequently creating fantastical pictures of princesses and sorceresses. Her inventive mind leads to the creation of the weekly allowance-sharing club, sparking the family's weekend excursions into the city.

The youngest Melendy sibling, Oliver is a calm and thoughtful six-year-old with a fascination for trains. He diligently completes household chores like watering plants and feeding the pets. Despite his youth and smaller allowance, Oliver possesses an independent streak and a desire to be as grown-up as his older siblings, carefully planning his own unaccompanied adventures.

The widowed patriarch of the Melendy family, Father works hard to balance his professional life with parenting. He is a patient, flexible parent who supports his children's desire for independence, setting reasonable safety boundaries while trusting their judgment. His calm demeanor ensures that the children feel safe confessing their occasional missteps.

The live-in housekeeper and cook for the Melendy family, Cuffy serves as a substitute mother, grandmother, and aunt to the children. She rules the household with firm authority but provides immense affection and understanding. She fondly remembers her youthful travels through Europe and maintains strict rules about safety, hygiene, and nutrition.

An elegant, older French woman who lives near the Melendys and wears expensive furs and necklaces. Raised in an overly sheltered and wealthy Parisian household in the 1800s, she has lived a life that includes a dramatic kidnapping by a fortune teller. She proves to be a generous friend and engaging storyteller, offering the children a new perspective on their world.

A small stray mutt with long ears and large, melting eyes. Rescued from a snowy alleyway, Isaac is wet, unkempt, and shivering when he first arrives at the Melendy house. He quickly integrates into the household, proving himself to be a smart, affectionate, and surprisingly helpful companion to the children.

An assistant at the Broadway hair salon Mona visits. Miss Pearl is brave and hardworking, having run away to New York City with her brother to escape an impoverished childhood and a cruel stepmother. She shares her dramatic life story while working and offers a dose of real-world perspective.

A hairdresser at the Broadway salon. He provides Mona with her dramatic new bob haircut, completing the transformation she spontaneously requests during her Saturday adventure.

The plumber and handyman who services the Melendy household. He is somewhat unimpressed by high art, having seen one Italian opera and disliked it, but remains practical and helpful during household emergencies.

A painter from Mrs. Oliphant's youth. He first sparked her imagination with tales of traveling carnivals, eventually rescuing her from captivity and painting her portrait, "The Princess," which hangs in the local art gallery.

A fortune teller who operated out of a wagon at a Parisian carnival in the 1800s. Recognizing a wealthy, sheltered child, she tied up and kidnapped a young Mrs. Oliphant for weeks before the girl managed to escape.