Dor is a man from ancient history who becomes the first person to measure time. Driven by an innate curiosity about numbers, shadows, and the movements of celestial bodies, he invents early calendars and clocks. His intellectual obsession distances him from his community and family. As punishment for trying to control time, he is banished to a cave where he becomes the immortal Father Time.

Sarah is a socially isolated high school student with a talent for science and math. Believing she is unappealing and awkward, she struggles with low self-esteem following her parents' divorce. She volunteers at a local homeless shelter to bolster her college applications, where she develops a crush on a fellow volunteer. She desperately counts the minutes until she can see him, wishing to freeze happy moments.

Victor is an immensely wealthy businessman in his mid-eighties battling kidney failure and cancer. Having lost his parents at a young age, he learned to avoid emotional attachments and focus on productivity. Unwilling to accept his terminal diagnosis, he begins secretly researching cryonics to extend his life.

The Old Man is a mysterious, supernatural figure who wears a white robe and carries a golden staff. He acts as a messenger of God and monitors humanity's technological boundaries. He intervenes when Dor begins measuring time, ultimately confining him to the cave and setting the conditions for his freedom.

Alli is Dor's childhood friend and eventual wife. She values human connection, family, and community over intellectual pursuits or power. She feels the pain of Dor's isolation and his obsession with timekeeping, mourning the loss of their children when they are forced into exile.

Nim is an ambitious leader in the ancient world who grows up alongside Dor and Alli. He seeks to amass wealth, enslave others, and conquer the heavens by building a massive tower. He demands that Dor use his knowledge of time to enhance his kingdom's power, rejecting any limits on his authority.

Ethan is a popular high school student who volunteers at a local shelter alongside Sarah. He is casually dismissive and shows little genuine interest in Sarah's feelings, frequently giving vague answers or canceling plans at the last minute. He enjoys the attention she gives him but refuses to commit to any real connection.

Lorraine is Sarah's mother, a woman trying to manage life and loneliness following her divorce. She loves her daughter but struggles to communicate with her, missing the days when they shared a closer bond. She lacks strict boundaries, leaving her largely unaware of Sarah's private struggles and social isolation.

Grace is Victor's dedicated wife of over forty years. Originally a bookkeeper who lost her first husband in the Korean War, she bonded with Victor over their mutual dedication to work. Though their marriage has grown distant over the decades, she attempts to reconnect with him by preparing healthy meals and staying by his side during his illness.

Tom is Sarah's father, who moved away to start a new family following his divorce from Lorraine. He originally bonded with Sarah over their shared interest in science and math, leaving a void in her life when he departed.

Jed is an employee at a cryonics warehouse. He provides Victor with facility tours and paperwork, referring to the frozen bodies as patients. He handles the legal and physical arrangements for those seeking to pause their mortality.

Roger is Victor's loyal personal assistant. He handles Victor's schedule, pushes his wheelchair, and ensures the businessman can continue reviewing portfolios and making arrangements despite his failing health.