Albert is a 26-year-old patent clerk living in 1905 Berne. Exhausted and physically unkempt from months of obsessive dreaming, he spends his waking hours trying to formulate a unifying theory of time to get closer to God, whom he calls "The Old One." His intense fixation on theoretical physics often leaves him detached from his physical needs and disconnected from his young family.

Michele is an engineer and Albert's closest friend. Practical and generous, he worries constantly about Albert's lack of sleep, poor eating habits, and strained marriage. He provides an emotional anchor and practical companionship to his brilliant but distant friend, often accompanying him on walks or fishing trips while quietly admiring his scientific ambition.

Mileva is a former physics student and Albert's wife. She shares a home with Albert in Berne and cares for their infant son, but she remains emotionally and intellectually isolated from her husband due to his total consumption by his work. She occasionally has to retrieve him from the patent office when he works through dinner.

Hans Albert is the infant son of Albert and Mileva. He lives in Berne with his parents but rarely interacts with his father, who is entirely consumed by the theoretical physics research that dominates their household.