John, [David Lee Smith], now going by the surname Young, teaches comparative religion at a community college in Chico, California. He is well-liked by students and married to fellow faculty member Carolyn Kittriss [Vanessa Williams]. For the first time in his life, John shows signs of ageing, and a hunting trip cut hints that his regenerative abilities are diminishing. When Isabel [Akemi Look], an enthusiastic student, is allowed to borrow books from John's collection, she discovers one authored by Dr. Jenkins and signed for John Oldman. Curious, Isabel learns about another, controversial book he authored, an account of the 14,000-year-old John Oldman. Drawing parallels between Oldman and their teacher, she shares the discovery with her classmates the four: Tara [Brittany Curran], Liko [Carlos Knight] and Philip [Sterling Knight]. They are open to the possibility that they are the same person, although Philip's faith is challenged by the book's claim that John was Jesus Christ. Their suspicions are confirmed when they obtain the book and see the only photo of Oldman, who is described as averse to being photographed to facilitate forging new identities.
Isabel attempts to contact Dr. Jenkins by email, but he rudely rejects her, assuming she is yet another person seeking to ridicule him. Undeterred, Isabel, Tara [Brittany Curran] and Liko [Carlos Knight] trespass into the Young household, discovering several books authored by John under various surnames. They also find a painting believed to be by Vincent van Gogh, which Isabel's cousin, an art major, considers possibly authentic supporting the book's claim that John had known van Gogh personally. The group later contacts a retired university professor who recalls meeting John during the 1950s.
Isabel leaves a voice message for Jenkins, but this time he is interested when she mentions John Young and agrees to meet them on the condition that they first provide a clear photo of John's face. After unsuccessful attempts to take a picture in class, they go into his house at night and photograph him while he is asleep. Jenkins, although somewhat hesitant as the purported John appears aged, agrees.
Shortly afterward, Tara visits John in his office. He becomes concerned when she cryptically claims to know his true identity. In tears, Tara explains that she has always felt lonely as well. When John attempts to comfort her, she makes a sexual advance, which he rejects, asking her to leave. Isabel scolds Tara when she confesses the incident, fearing that John may leave before Jenkins arrives. John is indeed preparing for departure, and his refusal to offer an explanation leads to an argument with his wife. That evening, the four confront John about the book's veracity. He admits to being Oldman but insists that the story was a fabrication and expresses regret that Jenkins damaged his own reputation by publishing it. To stop him, John is tased and restrained in his basement, assigning Philip to watch him while the others attempt to retrieve Jenkins, whose car has broken down nearby.
Upon regaining consciousness, John warns Philip that their actions are criminal but offers not to report them if he is released. Philip, however, persists in questioning John about Jesus. After a few evasions, John finally admits to having been Jesus, explaining that he has avoided garnering attention since witnessing the distortion of his moral teachings. Although Philip initially welcomes the idea that John is divine despite telling the truth, the situation becomes tense when John expresses that all religious paths lead to salvation. Recounting the Book of Revelation, Philip renounces John as the seven-headed beast and stabs him.
When Jenkins, Isabel, Liko and Tara arrive, they are shocked to find blood stains throughout the house, with both John and Philip missing. Weeks later, John has been hiding in the wilderness, and he arranges to meet with Harry [John Billingsley]. They speculate that his aging might result from the Holocene itself ending to herald the Anthropocene. John accepts Harry's invitation to live with his family.
Back in his home, Jenkins is visited by an FBI agent who knows about John's many identities and extraordinary age, adding that he is a suspect in many violent crimes, including Philip's disappearance. When he asks Jenkins whether he believes an immortal serial killer is possible, Jenkins replies that anything is.
