A 12-year-old Austrian Jewish boy living in Lemberg. Initially timid, he carries a heavy burden of guilt over his inability to prevent a historical tragedy, causing him to refuse a military honor from his father. When enemy forces occupy his hometown, he must set aside his fears to protect his family.

A 13-year-old British girl who studies medical texts and aspires to become a doctor. Seeking to honor the memory of her late father, who died heroically, she joins an ambulance train as an orderly. She possesses a firm moral compass, prioritizing immediate compassion for wounded individuals over strict military protocols.

A resilient French girl from Lille whose family is separated during a chaotic evacuation. Driven by a singular goal to gather enough money to bribe officers for her father's release, she faces near-constant obstacles. She survives by relying on the kindness of strangers and shares her warmth with others through a distinctive red knitted hat.

A 14-year-old Russian soldier who fights not out of ideological loyalty, but to earn enough money to buy his family's freedom from poverty. He often looks up at the sky to mentally escape the horrors of trench warfare, harboring a deep desire for a peaceful life away from constant conflict.

An 11-year-old German girl and daughter of an influential military officer. At the outbreak of the conflict, she enthusiastically supports her country's military strength, using playing cards to explain international alliances. As the situation in her country deteriorates, bringing starvation and illness to her doorstep, her understanding of the world dramatically matures.

Elsa's father and a prominent officer in the German military. Initially steadfast in his belief in imperial superiority, his experiences on the front lines and his interactions with prisoners test his dedication to his orders. His shifting perspective makes him a central figure in the lives of the young protagonists.

An imposing Russian officer leading the occupation forces. He demands absolute obedience from the civilians he oversees and the soldiers under his command. Believing that anger is the essential fuel for survival, he frequently antagonizes those who question his authority.

Felix's father, a Jewish businessman serving in the Austro-Hungarian military. He attempts to impart practical lessons about bravery to his son before reporting for duty. His Golden Cross of Merit serves as a significant emblem of courage passed among the young protagonists.

A protective mother who stays behind in Lemberg when the Russian army approaches. She attempts to shield the local Jewish community by navigating dangerous social dynamics with the occupying forces, teaching Felix that courage is a better tool for survival than anger.

A skilled nurse who accepts a position on a Red Cross ambulance train. She is dedicated to healing others and tries to prepare her daughter Kara for the gruesome reality of treating wounded soldiers near the battlefields.

A desperate mother who becomes separated from her daughter during a chaotic flight from the advancing military. She spends much of the war trying to keep her sons safe in a cave while hoping to reunite with Juliette.

Juliette's father and a civic leader in Lille who is held hostage. His imprisonment drives Juliette's actions throughout the conflict, and he eventually forms an unlikely connection with the German officer in charge of him.

Elsa's mother and Major Dressler's wife. She helps orchestrate the rescue of Felix and his mother from occupied territory early in the conflict. Later, she suffers from the Spanish flu and endures social ostracization directed at her family in Germany.

A young French girl whose mother has been imprisoned by the Germans for failing to pay taxes. She offers Juliette a place to stay, but struggles with deep desperation that leads to complex choices testing their friendship.

A Bolshevik Russian soldier and Dimitri's close companion. He watches out for Dimitri during battles and keeps a stitched red star as a symbol of an impending revolution and hope for civilian freedom.

A strict medical officer on the British ambulance train. He insists on rigid adherence to rules and military protocols, prioritizing obedience even when it conflicts with individual acts of compassion.

An officer who coordinates the orderlies on the ambulance train. During a dangerous extraction near a gas attack, he suffers a broken leg and requires emergency intervention.

One of Juliette's younger brothers who travels with their mother while hiding from the advancing forces.

Juliette's other younger brother, who stays hidden with their mother during their prolonged separation from the rest of the family.