Richard is a career-minded executive struggling with a severe, consuming nicotine addiction. He finds himself constantly thinking about his next cigarette, viewing his habit with distaste but unable to stop. After receiving a plain white business card from a former smoker, he reluctantly visits the midtown Manhattan office of Quitters, Inc., pulling him into a highly stressful behavioral modification program.

Vic is an addiction counselor at Quitters, Inc. who operates more like a mafia enforcer than a traditional therapist. A self-described pragmatist, he uses severe behavioral modification techniques and extreme aversion training to ensure his clients stop smoking. He maintains a composed, well-spoken exterior that barely conceals his willingness to use violence and intimidation to achieve his company's goals.

Cindy is Richard's wife and a cautious, hopeful supporter of his attempt to recover from nicotine addiction. Unaware of the extreme methods employed by Quitters, Inc., she believes her husband is simply undergoing a standard treatment. Her well-being acts as a central motivating force for Richard's behavior throughout the program.

Jimmy is Richard's old college friend and a successful advertising executive. Formerly a sickly chain-smoker, he has dramatically transformed his health and life after utilizing the services of Quitters, Inc. He acts as the catalyst for Richard's journey by giving him the organization's business card and praising their effectiveness.

Junk is a gruff, heavily built employee at Quitters, Inc. who handles the organization's physical enforcement. Built like a caricature of mob muscle, he wears a t-shirt bearing the word "SMILE" and exists solely to ensure clients comply with the company's aggressive behavioral modification methods.

The unnamed receptionist at Quitters, Inc. maintains a relentlessly pleasant, business-as-usual demeanor. Her constant, twinkling smile provides a jarring contrast to the violent, intimidating methods employed by the counselors and enforcers working behind the closed doors of the facility.

Alvin is Richard and Cindy's son. He represents an important part of Richard's home life and serves as an additional motivation for Richard to stick to the harsh rules imposed by his new recovery program.

Mrs. McCann is Jimmy's wife. Like Cindy Morrison, her life is directly impacted by her husband's involvement with the extreme addiction recovery methods practiced by Quitters, Inc.