Through a series of secret agreements, the great German philosopher Friedrich Nietzsche and the Austrian doctor Josef Breuer, one of the fathers of psychoanalysis, meet in 19th-century Vienna in an inspired process of dual psychotherapy. In this adventure of existential search involving two unique individuals, a young intern named Sigmund Freud, a tempestuous woman idolized by poets and psychiatrists, Lou Salome, and a captivating patient, Anna O., who haunts her doctor's soul, also become involved. In this novel, the famous psychiatrist Irvin D. Yalom invents the meeting of two historical figures in the metropolis of intellectual ferment of the 19th century, Vienna, offering an interpretative version of the birth of psychotherapy and its relationship with existential philosophy. The psychotherapeutic adventure that unfolds is breathtaking as it reveals step by step the healing power of a true relationship.