The inseparable bond between identical twins Jean and Paul is shattered when Jean attempts to assert his individuality, forcing Paul into a global search for his missing half. As the twins transition from a symbiotic childhood into adulthood, their shared identity—referred to by others as 'Jean-Paul'—becomes a source of both comfort and suffocating restriction. Paul, the more devoted of the two, struggles to navigate a world that demands he exist as a singular entity, while Jean seeks autonomy through external relationships. The narrative follows Paul’s pilgrimage across diverse international landscapes, serving as a physical manifestation of their psychological fracture and the inherent pain of human separation.

This work is widely regarded as a sophisticated exploration of the psychological and philosophical implications of twinship. Critics often highlight the author's ability to weave intricate imagery with a narrative that spans continents to reflect the internal state of the protagonists. The novel is noted for its refusal to shy away from the complexities of human connection and the often painful process of self-actualization. Readers frequently observe that the prose maintains a balance between intellectual depth and a distinct, dry humor that prevents the story from becoming overly somber. The text remains a significant example of how literature can examine the boundaries of the self through the lens of a singular, intense relationship.