Season 1

In season 1, the Man and his book are found at Cadillac Jack's, a diner, where he is waited on by Doris, and is seen, with moral ambiguity, to offer each of the visiting characters a deal toward her or his desire in return for the completion of a task.

• James (Matt Nolan) is in his early 30s. He has a wife and two children: a young boy and girl. His son has leukemia and is currently hospitalized. To save his son, he has to select and murder a little girl, and once chosen, he cannot pick another child. The Man tasks another client, Willem, to protect the child (Elizabeth). Eventually the two men become aware of each other and their conflicting tasks; this ultimately results in Willem kidnapping Elizabeth to keep her safe from James' attempts to kill her. When James begins tracking Willem in order to find the girl, he attacks James in his home, and James kills him in self-defense. James then follows the clues left behind to find Elizabeth, but decides not to kill her. Despite not fulfilling the task, James' son is cured of leukemia. James demands answers from the Man, who simply replies that he never guaranteed a refusal to carry out the task would result in his son's death.
• Jenny (Kate Maberly) wants to be prettier, and is told to steal $101,043 from a bank or series of banks. She prepares to steal from a bank by buying a gun and scoping out possible banks. During her preparations, she meets Richard, who lives in a car and makes his living by stealing from banks. Jenny brings Richard to meet the Man, and Richard tells the Man that he wishes his father, a cop, would leave him alone. For his task, Richard is told to help Jenny rob banks. She and Richard then attempt to rob a bank, but a shootout occurs and Jenny is shot in the arm. Richard then comes to the Man without Jenny to ask that she accept herself the way she is. Richard is given a new task to call his father, the detective, and tell him he loved him. Rather than continue the task of robbing banks to make Jenny prettier, they decide to leave town.
• Willem (Matt Boren) has a friend who attributed his success to the Man at the booth at the end. He approaches the Man hoping to get a woman from the centerfold in a magazine. The Man tasks him with protecting a little girl, Elizabeth, for a period of ten weeks. In order to protect the girl, Willem takes up jobs as a janitor at Elizabeth's school and as a gardener on Elizabeth's street. After he saves her from a speeding car (driven by James), Willem is lauded as a hero by her family, but he realizes that there is a man after Elizabeth's life. He decides to kidnap Elizabeth to keep her safe under his watch, at least until his time as her protector is up. Feeling inferior, Willem wants to be a hero, so he doesn't have to get his happiness from making deals. Willem soon realizes that James is following him to gain knowledge on the whereabouts of Elizabeth. Unnerved, Willem decides to kill James to protect Elizabeth. He breaks into James' house and attempts to stab James with a knife; however, James manages to take the knife away and kills Willem in self-defense.
• Mrs. Tyler (Norma Michaels), who in order to cure her husband's Alzheimer's, is expected to build a bomb and use it to kill an unmentioned number of people at Andy's, a coffee shop she had chosen. She builds the bomb using information she finds on the internet. She plans to place the bomb at a coffee shop at a time when many people would frequent it. The next time she sees the Man, she claims to have set it off; however, she had been lying. The Man knew she was lying because if she had set it off, she would already have what she wanted. Mrs. Tyler wavers, unwilling to set the bomb off, yet strongly desiring to have her husband whole again. She tells the Man that she decided against detonating the bomb, and found out that her husband had been spontaneously cured: he never had Alzheimer's, but a mis-diagnosis of Normal Pressure Hydrocephalus which was giving him the same symptoms.
• Melody (Jennifer Del Rosario) is a 17-year-old girl, charming and positive. She loves her father, and wants him to be happy again – like he was before his business started having trouble – and the Man tells her to get a shut-in out of his home. Melody volunteers with a shut-in and slowly builds his trust. He remains unwilling to leave his house and she discovers evidence that he is actually a serial killer. When the police ignore her, she plans to drug the shut-in and drag him out of the house. While she successfully drugs the man, he is not completely unconscious and attacks her while she is dragging him. She is able to drag him out of the house, but then succumbs to her wounds and dies. However, her wish is fulfilled and her father's financial problems are resolved.
• Allen (Jack Conley), a detective in his 40s, is a hard-edged man with a violent streak he tries valiantly to control. He is expected to kill a man in order to locate the money stolen from a bank. Allen initially lies to the Man and does not receive the money, until he later kills the person in his lie. When complete he is angered that he found the money, but not the bank robber (who turns out to be his son Richard, Jenny's accomplice and also a client of the Man), leading him to ask for a second deal, for his son to come home. For this, he has to hide a fellow cop's criminal behavior. He tracks down a corrupt cop, a homicide detective who has been stealing from murder victims. However when his son calls him and tells him he loves him, Allen realizes that he himself is a corrupt cop. He decides to turn himself in for his earlier murder.
• Sister Carmel (Sarah Clarke) is a nun in her mid-30s who is losing her faith. She says God once spoke to her, but she no longer hears him. The Man tells her to become pregnant. Sister Carmel sneaks out of the convent to start dating. Eventually she meets Simon and begins a relationship with him. In the end she happily tells the Man that she is certain she is pregnant and God is talking to her again. Simon reveals her real name is Margaret.
• Doris (Jenni Blong) is a waitress in the diner the Man operates from, observing the comings and goings of his "clients." Curious, she strikes up a conversation with the Man, trying to find out who he is and what he's doing with all these people. Unlike the other characters she isn't looking for anything and has no need to make a deal with the Man. This throws the Man off guard, and causes him to reveal things about himself that no one else would discover. This leads to him making a request, rather than soliciting one.
• Simon (Timothy Omundson), an artist in his early 40s, has devoted his life to painting. Despite technical craftsmanship, he has yet to make paintings as beautiful as he wants to make. He will do anything to finally accomplish this, and is tasked with becoming a father. He finally succeeds by painting a portrait of Sister Carmel, with whom he begins a relationship.
• Richard (Jake Richardson) is Allen's son, and is part of Jenny's story. He is tattooed, hotheaded and a thief. He ends up making a deal with the Man to be left alone by his father, for which he has to help Jenny rob banks. Subsequently, he wants to stop Jenny wanting what she wants, and is tasked with telling his father he loves him.
• Gerald (Anthony Wong) is Melody's father. He explains that Melody succeeded in dragging the shut-in out of his apartment, but died as a result of the injuries the man gave her. Though he is unaware of the connection to the man in the booth, since she succeeded in her task, Gerald's money problems disappeared. He comes to the Man wanting to bring his daughter back to life, and the Man tells him, "That can happen." The episode ends before Gerald is given his task.

Season 2

In season 2, the Man has changed his diner and left behind Doris as waitress (and, seemingly, has changed the appearance of his book and pen). He continues to offer patrons deals toward their desires, in return for the completion of tasks. The season reveals more regarding both the Man and his nature, regarding the mysterious book that is the source of the tasks, and regarding the character of Doris from season 1.

• Cheryl (Michelle Allsopp), a mother in her late 30s, has a daughter suffering from an undisclosed debilitating disorder, who asks for her daughter to be healed of her condition. The initial task given to her is to find a woman without friends or family and to torture her. Cheryl locates a potential victim but is unable to carry through with the task. Cheryl then wishes to accept her daughter as she is and is given the new task of abandoning her family for three weeks without word or warning. The Man even offers his own personal help. After the three weeks Cheryl returns to the diner fully accepting her daughter for who she is.
• Doris (Jenni Blong), featured in season 1, returns. Initially she informs the Man that Melody had survived her attack in season 1, referring to the deal struck in the close of the final episode. Doris appears to be more than a simple waitress as she knows about the book. She and the man allude to a common origin (and possible enmity). He notes that he should have noticed when they first met. She begins asking him about why he makes the deals and the book he uses. In a reversing of roles, the Man asks for her to use the book to make him a deal; he wants to understand people. He is tasked with picking a person and helping them. Subsequently, he volunteers to assist Cheryl with her task, bringing her food and supplies while she hides out. In the final segment of season 2, after debriefing him on his task and newfound understanding, she announces that she wants to make a deal herself: for him to love her.
• Conner (Keegan Boos) is brought by his friend Bobby to meet the Man. Conner's mother has thrown out his father; Conner asks for his return and for him to stop drinking. After some initial reluctance on the Man's behalf, the Man gives them the task of finding and returning a missing person home. The boys learn of Cheryl's recent disappearance and seek to find her. Conner discovers Cheryl on his own; the two talk, and though neither reveals their task or connection to the man in the booth, she agrees that when she is ready, she will let Conner be the one to "find" her. Eventually Conner is the one to bring Cheryl home.
• Jack (Dayton Callie), an elderly man, returns repeatedly to the diner to tell the man of his exploits in robbing a number of persons. This thievery is in return to "protect his grandchildren" by stopping the construction of an unnamed religious site. However his desire turns more vicious as he wants the complete eradication of all that faith's believers. To do so Jack must commit a public attack slaughtering twenty-two in broad daylight with others bearing witness. Jack begins to plan and set up for these attacks, becoming increasingly enthusiastic about it as he nears readiness. He has a chance encounter with Henry and decides that he must execute his task right away. On the day of the planned slaughter, Henry tries to stop him, inadvertently killing him.
• Melody (Jennifer Del Rosario) returns for season 2. She confronts the Man, demanding answers about what happened to her, believing that she was dead and that another woman died in her place in order to bring her back to life. She wishes for their places to be reversed. Her task is making something worth living for. She decides to start a garden giving her a chance encounter with Dillon. The pair exchange each other's pains. When sharing this with the Man, she is given one more opportunity to revoke the deal but wishes to go through with it. She dies in her sleep.
• Dillon (Noel Fisher), a young man in his early 20s, fears the entirety of death. Upon their first meeting, Dillon tells the Man that he wishes to be invulnerable and live forever without changing so that he may enjoy his life. The Man is hesitant to help demanding that Dillon be honest with him. Dillon's finally reveals that his father died while serving in the military. It was set to be a closed casket, but Dillon removed the bolts revealing what remained of his father. Dillon is tasked with marking three people, but must determine what this means on his own in order to do so. His first attempt of breaking another man's nose in a fight is not acknowledged by the book. After a chance encounter with Melody, Dillon "marks" her by sharing his feelings, fears and experiences with her. After her death he returns to the diner and breaks off the deal, citing that she had marked him as well, something his wish would make impossible in the future.
• Theresa (Abby Miller) is a plain woman, only asking to be loved. She is tasked with approaching a number of men and making sexual advances towards them. She is also struggling with being her nephew's guardian, as he struggles with anger issues which cause problems at school and at home. As she nears the end of the task his anger issues subside and he shows a newfound lovingness towards her. She begins to fear this is the love bargained for in her deal, and considers asking for a new one specific to finding romantic love but worries that abandoning her current task will return her nephew's anger problem. While she is struggling with the decision, a stranger (possibly the man from the booth) follows her home one night, comes to her door and tells her that she is "worth more". She leaves the diner one last time happy with herself.
• Henry (Danny Nucci), a man in his late 30s, is unhappy with his life and wishes that instead of marrying his current wife Heather, he would have instead been married to his past sweetheart Katie. Henry wants to just have been happily married for twenty years, not to have experienced those years or to relive those years, but just to wake up having been married to Katie for two decades. His task is to become a servant to a higher power. This is particularly vexing to Henry, who insists he is an atheist and finds the concept of God foolish. After some reluctance and confusion Henry crosses paths with Jack as Jack is scoping out a place for his task. On the day Jack plans to finish his task, Henry runs forward and tackles Jack. During the struggle Jack is shot and killed. Returning to the diner, Henry decides to revoke the deal and just live his life.
• Maria (Romina Peniche) is concerned about her mother, who is unhappy after the death of her husband and the institutionalization of her other daughter due to drug addiction. Maria wishes her mother to be broken free of her depression and to be filled with love for the rest of her days. In return, she is given the task of making five people cry. However she finds it quite difficult to make anyone cry, including random children at the zoo, an ex lover, and a baby. She finally is successful in helping a grieving boy finally cry after the loss of his mother. Maria tells the stories of her failed attempts to complete the task to her mother, making her laugh and bringing some joy back to her life. At this Maria has accomplished what she wanted and says farewell to the Man.
• Bobby (Brendan Chadd Thomas) is a young boy who desires to help his friend Conner. Despite the Man's initial reluctance, Bobby returns to the diner with Conner. After explaining the potential costs, the Man proceeds to offer the boys a task: find and bring home a missing person.

Season 1 (2010)

The episodes of the first season were directed by Jessica Landaw.

Season 2 (2012)

The episodes of the second season were directed by Adam Arkin.