Maks is a thirteen-year-old Danish immigrant who dropped out of school to sell newspapers to support his family. He lives in a cramped tenement on the Lower East Side of New York City in 1893. He is optimistic and observant, finding joy in the diverse community around him despite the grinding poverty. When his sister goes to prison, he takes on the role of an undercover investigator to prove her innocence.

Willa is a homeless orphan who survives by scavenging at the city dump and sleeping in an alley between two fences. She is extremely cautious, carrying a large tree branch for protection. Underneath her fearful exterior, she holds onto memories of a better life, represented by a blue tin box and a porcelain doll she keeps hidden. She finds temporary safety when Maks invites her into his tenement home.

Emma is a teenage Danish immigrant who works as a maid at the luxurious Waldorf Hotel. She is arrested and imprisoned after being accused of stealing a valuable watch from a hotel guest. She suffers immensely in the harsh conditions of the adult prison, relying on visits and food brought by her family as she awaits trial and faces possible deportation.

Bruno is a teenage bully with red hair who leads a local street gang on the Lower East Side. He routinely terrorizes the newsboys, stealing their money and using violence to assert his dominance. Beneath his aggressive street persona, he is a solitary boy living in a secret hole next to an abandoned saloon, operating under the heavy thumb of a dangerous mobster.

Brunswick is a well-dressed, pistol-carrying criminal who stays at the Waldorf Hotel. He acts as a cruel and demanding boss, using blackmail to force younger street thugs into orchestrating attacks against local newspaper boys to control the media narrative.

Agnes is a fourteen-year-old girl who works alongside her father at a shoe factory to help support the family. She aggressively pursues assimilation into American culture, correcting her siblings' grammar and taking typing classes at night to secure a better job. She attempts to hide a persistent cough, concealing the physical toll of her grueling schedule.

Bartleby Donck is a former detective who now acts as an eccentric advocate for the city's poorest children. He suffers from advanced illness, using a tube-like contraption to hear and living in utter squalor. Despite his cynical manner and failing health, he uses his sharp mind to teach local children the basics of investigation.

Mama Geless is a hardworking immigrant who takes in laundry to help support her large household. She deeply misses her homeland and struggles with the harsh realities of American city life, frequently relying on her cultural traditions for comfort. She shows immense compassion by welcoming a homeless orphan into her already overcrowded home.

Papa Geless works long hours cutting materials at a shoe factory to keep his family afloat. He is an emotional man who struggles to handle the stress of the legal system, often sinking into despair or singing sad folk songs. He provides steady affection to his children and readily accepts a new member into the family.

Jacob is an eight-year-old boy who occasionally helps sell newspapers and looks up to his older brother. He enjoys listening to dime-novel stories read aloud in the evening and tries to help out when emergencies arise.

Ryker is the youngest boy in the Geless family. He attends local classes, where his teacher renames him Ronald to sound more American, reflecting the intense pressures of assimilation on immigrant children.

Eric is one of the younger children in the tenement. He shares a crowded bedroom with his brothers and helps keep quiet about the family's legal troubles.

Monsieur Zulot is a French immigrant who boards with the family, paying a crucial dollar a week in rent. He entertains the younger boys by reading detective stories and harbors a quiet affection for the oldest daughter at home.

Mr. Packwood manages the luxurious Waldorf Hotel where a valuable item goes missing. He maintains strict standards for his wealthy establishment but agrees to arrange a service job as a favor to an old friend.

Chimmie is a fellow newspaper salesman who understands the dangers of the street. He provides a crucial tip about a local detective who might be able to help with legal troubles.

Mr. Trevor manages the bellboys at the Waldorf. He gives daily assignments and room requests, inadvertently helping an undercover boy gather clues about the guests.

Miss Foley is the supervisor in charge of the maids. She expresses a negative opinion of her staff when questioned about the hotel's missing property.

Maud is a well-dressed woman who shares a complicated past with a local detective, having turned down his marriage proposal years ago due to his poverty.

Rory is a fellow newspaper salesman on the streets of New York. He shares rumors and warnings about the increasing dangers posed by the local street gangs.

Abe is a young newspaper boy who suffers a battered arm following a brutal attack by a local street gang. His injury highlights the physical dangers the children face while trying to earn a living.

Joe Gorker is a corrupt political boss facing trial for embezzlement. He is later spotted dining at the luxurious Men's Club inside the hotel alongside other wealthy individuals.