A short film adaptation from the book of the same name by Miguel de Unamuno. The plot revolves around the character of Augusto, an introverted young man who falls in love with a young woman named Eugenia as she walks past him on the street, and he sets about trying to court her. In the meantime, Augusto becomes involved with another girl, Rosario, and he begins to question if he is really in love with Eugenia at all. The title, Spanish for 'fog', is a reference to how Augusto sees his life. Augusto describes his world as full of small and almost imperceptible occurrences, some of them good, some of them bad, that all serve to obscure his vision.

A group of friends in a car give a ride to a stranger who will affect their lives indirectly.