Josef is a 40-year-old eminent physician in Vienna who recently discovered the role of the inner ear in regulating balance. Despite professional success and a wealthy household, he suffers from severe existential anxiety about aging and death. He obsessively fixates on a former patient as a psychological defense against his dread. He frequently works long hours, traveling the city in his horse-drawn fiacre, which isolates him from his wife and five children.

Friedrich is a 38-year-old German philosopher living a solitary, ascetic lifestyle after leaving his professorship at Basel. He suffers from severe, unexplained physical ailments including migraines, extreme nausea, and impending blindness. He self-medicates with chloral hydrate and resists any form of help that he perceives as a threat to his independence. He fiercely guards his emotional pain following a romantic rejection.

Lou is a highly independent young Russian woman who actively defies the social conventions of her era. Recognizing her friend's severe mental distress, she tracks down a prestigious doctor and persuades him to administer an experimental cure. She operates with absolute confidence, dictating the strict terms of the medical intervention to ensure the patient never discovers her involvement.

Sigmund is a 29-year-old physician who harbors ambitions of becoming a research scientist. His career progress is stalled due to pervasive antisemitism in the academic community. He possesses a brilliant, highly analytical mind and frequently acts as a sounding board for new medical theories, proposing early concepts about hidden layers of human consciousness.

Mathilde is a 36-year-old woman from one of Vienna's wealthiest families. She raises five children while managing a high-status household. She feels trapped by the societal limitations placed on Jewish women of her era and grows increasingly frustrated by her husband's constant absence and emotional coldness.

Bertha is a psychologically troubled young woman who previously sought treatment for severe physical and mental symptoms. During her highly unorthodox treatment, she coined the phrase 'talking cure.' She currently resides in an institution, struggling with a morphine addiction and unresolved trauma.

Max is a 40-year-old man who frequently attends dinners at his sister-in-law's home. He acts as a reluctant confidant to the host, often challenging the doctor's altruistic motives. Max freely admits to his own infidelities, using his pragmatic and sometimes vulgar worldview to contrast with his relative's intense moral anxieties.

Franz is a practical, deeply concerned friend who recognizes the physical deterioration of his companion. He actively researches medical options and successfully pushes his friend to seek specialized help.

Elizabeth is an intensely overprotective sister who aggressively screens the people around her sibling. She holds strong antisemitic views and views independent women as scandalous threats to her family's reputation.

Paul is a philosopher who inadvertently sets off a disastrous chain of events by introducing two highly volatile personalities. He originally intended to act as an academic mentor before romantic feelings complicated the group dynamic.

Eva is a former nurse who lost her position abruptly. She maintains a professional distance from her former employer, having completely forgotten an allegedly significant interaction that continues to haunt him.

Frau Becker is a pragmatic nurse who manages the daily operations of a busy medical clinic. She frequently offers her employer grounded advice, reminding him that he cannot force treatment on unwilling individuals.

Herr Schlagel is a former military officer who operates a local guesthouse. He keeps a close, slightly suspicious eye on his tenants and acts decisively when he discovers a medical emergency on his property.

Jenia is a young man who previously received experimental treatment for psychological distress. His successful therapy provides his family with the exact knowledge required to orchestrate a secret medical intervention.

Dr. Exner is a younger member of the psychiatry staff who became dangerously infatuated with a patient. Recognizing his compromised judgment, he formally withdrew from the medical team.

Richard is a world-renowned composer who utilizes his massive cultural influence to help a struggling friend. His written endorsement forces a skeptical doctor to take a medical case seriously.