Mikhail is an elderly man living in Michigan who decides to document his life's secrets on tape for his granddaughter, Kate, before his death. In his recordings, he claims that his true identity is Leonka Sednyov, the historical 14-year-old kitchen boy who worked for the Romanov family during their 1918 imprisonment. Through his detailed recollections, he provides a firsthand account of the royal family's final days at the Ipatiev House, seeking to unburden himself of decades-old memories.

Volodya is a young Bolshevik guard assigned to watch over the Romanov family during their imprisonment at the Ipatiev House in the summer of 1918. Like many of his comrades, he was recruited from the local working class, specifically the Zlokazov Factory, and drawn into the party's revolutionary activities. He observes the daily lives, struggles, and vulnerabilities of the royal family during their strict captivity under Bolshevik rule.

The former Emperor of Russia, Nikolai has been stripped of his power and imprisoned in the countryside by the Bolsheviks. Despite the humiliating and oppressive conditions, he maintains a gentlemanly composure and tries to negotiate calmly with his captors. He is a deeply devoted family man who prioritizes the safety and well-being of his wife and children above all else, even as political tensions escalate around them.

Aleksandra is the wife of Tsar Nikolai II and the former tsaritsa of Russia. She relies heavily on her religious faith to endure the family's imprisonment, believing fervently that outside forces are coming to rescue them. She leads her daughters in a desperate plan to sew their valuable gems into their corsets, hoping to smuggle their wealth out during an escape.

Aleksei is the only son of Tsar Nikolai II and Aleksandra, and the heir to the Russian throne. He suffers from hemophilia, a debilitating blood disease that frequently leaves him weak and unable to walk. Despite his physical limitations and the family's grim circumstances, he maintains a bright, enthusiastic energy that contrasts with the heavy atmosphere of the prison house.

Maria is the third daughter of Tsar Nikolai II and Tsaritsa Aleksandra. Like her sisters, she endures the stifling summer heat, sealed windows, and antagonistic guards at the Ipatiev House. She actively participates in her mother's desperate plans to stitch the family's precious jewels into their clothing in preparation for a potential rescue.

Novice Marina is a young ward of Sister Antonina in 1918, assisting the older nun in delivering fresh milk and food to the imprisoned Romanovs. Because the Bolsheviks allow the nuns access to the house, Marina plays a crucial role in the clandestine communication network forming around the royal family. Decades later, she is an elderly woman living in St. Petersburg who holds vital knowledge about the summer of 1918.

Yurovsky is a harsh, authoritative Bolshevik commander who takes over the guard detail at the Ipatiev House on July 5, 1918. He immediately tightens security, searches everybody who enters or leaves, and confiscates the Romanovs' valuables to store in a wooden box. His arrival signals a much more dangerous and restrictive phase of the royal family's captivity.

Kate (sometimes called Katya) is an American woman who receives a series of mysterious audio tapes from her grandfather, Mikhail Semyonov. Intrigued and unsettled by his claims of having been the Romanovs' kitchen boy, she travels to Russia to uncover the truth about his past. Her quest eventually leads her to St. Petersburg, where she seeks out historical witnesses to verify his extraordinary story.

Sister Antonina is a local nun who is permitted by the Bolsheviks to deliver fresh milk, eggs, and other food to the imprisoned Romanov family. She uses this access to smuggle secret letters hidden in bottle caps, acting as a vital link between the royal family and the outside world.

Dr. Botkin is the resident physician and a loyal friend to the Romanov family, choosing to share their imprisonment at the Ipatiev House. He treats Aleksei's medical condition and relies on the royal family and the kitchen boy for his own care when his health fails.

Avdeyev is the initial Bolshevik komendant in charge of guarding the Romanovs. He routinely antagonizes the royal family, refuses their requests to open windows in the stifling summer heat, and conducts strict daily inspections to ensure no one has escaped.

Tatyana is the second daughter of Tsar Nikolai and Tsaritsa Aleksandra. She endures the harsh conditions of their imprisonment and is visibly embarrassed and frightened by the Bolshevik guards' crude behavior, such as when they draw obscene graffiti in the bathroom.

Olga is the eldest daughter of the Romanov family. Alongside her mother and sisters, she spends her days quietly participating in the family's secret preparations, carefully stitching diamonds and other precious gems into the seams of her clothing in case a rescue attempt occurs.

Anastasiya is the youngest daughter of the Romanovs. She retains moments of youthful enthusiasm despite her imprisonment, such as dangerously climbing onto a windowsill for fresh air when a window is finally unsealed, nearly getting shot by a panicked guard in the process.

Father Storozhev is a local priest at the Church of the Ascension. He acts as an outside contact for the Romanovs, receiving the tsar's secret replies detailing the floor plan of the Ipatiev House to coordinate with a supposed rescue attempt.

May is the recently deceased wife of Mikhail Semyonov. Her death deeply affects him, prompting his decision to record his life's secrets on tape for their granddaughter, Kate, before he hopes to join May in heaven.

Kharitonov is the house chef who prepares meals for the imprisoned Romanov family. He teaches the royal daughters how to bake bread, reflecting the family's loss of royal privileges as they adapt to doing working-class chores.