David Moray is a wealthy physician in his fifties who lives in a Swiss villa, where he indulges his passion for collecting art. He is contemplating a relationship with the stylish yet impoverished Frida von Altishofer, but an idle comment overheard at a party brings an intoxicating memory from his youth. As an idealistic medical student, he once loved and planned to marry Mary Cameron, a simple, highland lass. But first, David had to take a long sea voyage as a ship doctor to recover from tuberculosis; there he met pouting but provocative Doris, and her hopeful parents.

The prospect of a fabulous income in the family’s drug business makes him abandon Mary and a medical practice. He marries Doris but within a short time she is permanently committed to an asylum. The family semi-apologizes for not having told him of her illness. David compensates for his miserable marriage with material possessions that are a proxy for self esteem, until Doris dies and sets him free.

The overhead remark sends him back to Scotland only to discover that his jilted Mary, who had married a minister, is now dead. Her daughter, Kathy, is a nurse and the very spit of her mother. He falls in love all over again. Kathy will not marry him unless he returns to practice and joins her and her uncle as missionaries in Africa. Full of good intentions, he agrees. But he does not tell Kathy about Mary, and he forces himself on her against her will.

When he assimilates the very real dangers of mission work, he simply fails to show up for the appointed rendezvous; he will marry Frida and keep his cherished possessions instead. Told bluntly by Frida of the marriage and of her mother’s past, Kathy drowns herself. David must identify her body. He then hangs himself from a Judas Tree.