Recovering from an illness, an observer in a London coffee shop becomes fixated on an indecipherable old man in the passing throng. Driven by curiosity, he follows the stranger through the city's labyrinthine streets from dusk until dawn, seeking the truth behind his erratic behavior. The story paints a haunting picture of urban alienation and the secret sins that hide in plain sight. It suggests that some mysteries of the human heart are too dark to ever be read.