Alan Austen is a young man driven by unrequited affection for a woman named Diana. He lacks practical relationship experience and holds a self-absorbed view of romance. He desires absolute affection but fails to consider the emotional restrictions of an artificially induced, obsessive attachment. His youth and impatience make him highly susceptible to the cynical business practices of the older shop owner.

The unnamed shop owner operates a secretive business selling mysterious liquids from dirty phials. He speaks in carefully constructed euphemisms, pitching his wares with the detached efficiency of an experienced salesman. He views romantic attachment with deep cynicism, recognizing that the fulfillment of youthful passion often creates a future demand for a much more expensive, permanent product.

Diana is an independent young woman who enjoys attending parties and socializing. She does not share Alan Austen's intense romantic feelings, preferring to maintain her freedom and outgoing lifestyle. Unseen in the physical narrative, she exists as the subject of Alan's pursuit, unaware of the artificial methods he plans to use to capture her attention.