The game follows the story of Sister Christina, a young nun who has dedicated her life to serving the Lord. As she embarks on a journey of spiritual exploration, she faces numerous challenges and trials that test her faith, her resolve, and her very sense of self. Through her experiences, players are invited to reflect on their own values and beliefs, and to consider the nature of devotion, sacrifice, and redemption.

The gameplay loop of The Passion of Sister Christina balances strict time management with traditional RPG exploration.

The core theme of The Passion of Sister Christina is the destructive power of external pressure on a fragile individual. Christina is not a willing participant in her downfall; she is a victim of circumstance, a "weak-willed sister" who is swept along by the demands of others. The game explores the theme of moral relativism in the face of desperation—how a person's convictions can erode as survival becomes the priority.