Mackenzie is a 29-year-old shapeshifter and ER doctor who has been working at Denver General Hospital for a single year. She secretly bears an omega designation, which she hides from her peers to avoid workplace discrimination and societal stereotypes regarding fertility and libido. Raised by her grandparents after her mother's death and her father's subsequent abandonment, she maintains a cheerful, sociable exterior that masks her deep fear of emotional commitment. To appease her matchmaking grandmother, she propositions a coworker for a fake relationship.

Noah is the 36-year-old head of the cardiology department at Denver General Hospital. A known prodigy in his field, he maintains a strict, standoffish demeanor that earns him the nickname "The Boogeyman" among the hospital staff. He is a rare alpha shifter who takes high-grade suppressants to hide his nature, fearing the institutional prejudice that targets alphas as overly aggressive. With his secret recently leaked to the medical board, he uses a fake mating to protect his career standing.

Dennis is a senior cardiologist at Denver General Hospital, older than Noah by a decade. He sports an unnaturally tanned complexion from frequent tanning bed usage and has graying hair. He harbors intense resentment over Noah's promotion to department head, firmly believing his own seniority entitled him to the role. He actively looks for ways to demean his younger boss in front of patients and staff.

Parker is an IT technician at Denver General Hospital and Mackenzie's closest confidant. Having known Mackenzie for sixteen years, he is intensely protective of her well-being. He expresses immediate skepticism regarding her decision to deceive the medical board and partner with a man known for his icy workplace reputation.

Liam is a highly competent registered nurse at Denver General Hospital. When Mackenzie first joined the staff, Liam acted as a guide and quickly developed unrequited romantic feelings for her. He views her sudden relationship with the department head as a terrible mistake and regularly vocalizes his poor opinion of the match.

Moira is Mackenzie's grandmother and surrogate mother. After the death of Mackenzie's mother, Moira and her husband assumed full guardianship. She operates as a relentless matchmaker, frequently arranging disastrous dates for her granddaughter in a determined effort to see her settle down.

Noah's mother is a persistent force in his life who refuses to let him isolate himself completely. She utilizes a wide network of local friends and acquaintances to gather information about her son's activities, frequently calling him to reprimand him for keeping secrets from the family.

Paul is a retired cardiologist and Noah's former mentor. Recognizing Noah's genius, Paul specifically nominated him to take over the department upon his own retirement. He is one of the very few individuals whom Noah trusts with the truth regarding his suppressed alpha designation.

Priya is the on-call anesthesiologist at Denver General Hospital. She is a highly sociable, serially single doctor who pays close attention to the hospital's internal social dynamics. She insists on dragging Mackenzie to staff events to verify the authenticity of the new romance.

Jessica is a hospital employee at Denver General who functions as the resident rumor mill. She actively monitors the social lives of the medical staff and ensures that any interesting developments, especially those involving the notoriously reclusive head of cardiology, circulate quickly through the hospital.

Vaughn is Parker's boyfriend. He acts as a supportive presence in Parker's life and integrates easily into Mackenzie's immediate social circle, offering fashion advice and attending group gatherings.