Near the end of A Dangerous Method, Carl Jung (Michael Fassbender) states that sometimes people must do horrible things just to continue living. In a way, this moment captures the essence of the film. Jung and Sigmund Freud (Viggo Mortensen) are arguably the most recognized contributors to psychotherapy, but A Dangerous Method explores the men’s personal lives and the little-told tale of Jung’s affair with one of his patients, Sabina Spielrein (Keira Knightley).

The cast all give stunning performances in their roles. Knightley plays Sabina as vulnerable but determined, shifting from madness to recovery while still retaining a glimmer of that pain that pushed her over the edge in the first place. Fassbender’s Jung is hungry for knowledge and the flesh, leading him to destroy all he loves. Mortensen’s Freud is inflexible, stifling, stubborn, and set on always having the upper hand. The film’s one shortcoming is that because it covers such a long time period, some development is lacking. There’s very little chemistry between Sabina and Jung before they have their affair, and Vincent Cassel’s delightful turn as hedonistic psychiatrist/patient Otto Gross is cut regretfully short, leaving him as little more than a vocalization of Jung’s primal urges.

Still, to judge the film for what it is rather than what it isn’t, A Dangerous Method is a fascinating look into the lives of people whose ideas have affected the way we all think about our mental health. It’s certainly not the most action-packed movie of the year, but if you enjoy character development and period pieces, then this is the pick for you.

A Dangerous Method opens November 23.