Raimund Gregorius (Jeremy Irons), affectionately called ‘Mundus’ by his students, is a high-school Latin teacher and an expert in ancient languages. His life is transformed following a mysterious encounter with a young Portuguese woman on the old Kirchenfeld Bridge in the beautiful Swiss city of Bern, whom he manages to save from jumping to her death in the icy waters below.

Raimund is intrigued but the woman disappears, leaving behind her coat. Inside it he discovers a book by a Portuguese doctor called Amadeu de Prado, which contains a train ticket. He spontaneously decides to use it, setting off on an adventurous journey to Lisbon. While looking for the author, Raimund revisits a dark chapter in the country’s history and unveils a tragic love triangle. He is drawn into a mysterious puzzle where the stakes are extremely high, riddled with political and emotional intrigue. Ultimately his journey transcends time and space, touching on matters of history, philosophy, and medicine, encountering love and evolving into a liberating search for the true meaning of life.