Peri is a Turkish woman who lives a domestic life in Istanbul but carries the weight of an unresolved past from her time as a student at Oxford University. Growing up in a household deeply divided over religion, she exists in a constant state of confusion between faith and disbelief. She relies on intellect and academic excellence to find self-worth, though her avoidance of conflict often results in a paralyzing passivity.

Mensur is Peri's fiercely secular father who values science, democracy, and education over religious faith. He actively disapproves of his wife's piety and places immense pressure on Peri to attend Oxford and rely solely on empirical truths. He battles a fondness for alcohol that negatively impacts his physical health.

Selma is a practicing Muslim whose strict adherence to her faith causes constant friction with her secular husband. She finds strength and security in religious rituals and places a high value on traditional modesty and morality. She is highly critical of Peri, maintaining a strained dynamic with her daughter.

Professor Azur is a celebrated and controversial academic at Oxford University who teaches a highly exclusive seminar on God. He is charismatic, widely published, and commands immense respect and fascination from his students. He actively challenges certainties, preferring to strip students of their preexisting dogmas to force intellectual growth.

Shirin is a confident, exuberant Oxford student of Iranian descent. Having moved across Europe after her family left Iran, she identifies as a staunch atheist and openly disdains organized religion. She plays a central role in introducing Peri to Professor Azur's seminar and frequently debates religious topics with her peers.

Mona is an Egyptian American student who proudly wears a headscarf. She defends her faith against prejudices from both non-Muslims and secular Muslims. She joins Peri and Shirin in their shared living arrangement, creating a dynamic tension in the household regarding religious practice and identity.

Deniz is Peri's thirteen-year-old daughter. She is observant and inquisitive, frequently asking questions about her mother's past when she finds the old Oxford Polaroid. She represents Peri's current domestic life and the generational shifts in their society.

Umut is Peri's eldest brother, a young man who aligns with his father's secular views but adopts a more extreme, Marxist ideology. His political activities bring severe consequences to the Nalbantoğlu household, leading to his imprisonment and torture, which forever alters the family dynamic.

Hakan is Peri's second older brother, who aligns closely with his mother's religious and conservative values. He drops out of university to join an ultra-nationalist newspaper. His strict adherence to traditional morality causes significant drama during his wedding.

Feride is a pious young woman whose family is even more religious than Selma. She faces a traumatic experience on her wedding night due to strict cultural expectations surrounding female purity.

Adnan is Peri's husband, a man significantly older than her. He belongs to the wealthy upper class of Istanbul and attends the high-society dinner party alongside his wife.

Troy is a disgruntled student at Oxford who harbors a deep animosity toward Professor Azur. He actively attempts to dissuade Peri from taking Azur's seminar and dedicates himself to gathering evidence to ruin the professor's reputation.

Dr. Raymond is a faculty member at Oxford who serves as Peri's advisor. He holds a critical view of Professor Azur's unorthodox teaching methods and tries to steer Peri toward a more conventional academic path.

Darren is a graduate student in physics at Oxford. He meets Peri during a holiday gathering and displays a clear romantic interest in her, offering a temporary distraction.

Ed is a student in Professor Azur's seminar. He credits the professor with helping him navigate a difficult personal period, demonstrating the deep personal influence Azur wields over his class.