Reese began on Chicago Med as a medical student learning the ropes from the more experienced doctors and nurses of Gaffney Chicago Medical Center, and often finding it difficult to keep up. Interacting with patients proves challenging for Sarah, not because of any sort of rudeness on her part or bad bedside manner, but because she's far too clinical with patients who need lay explanations of what's happening to their bodies. Eventually, she applies her talents in the pathology lab, but even that comes to an end.
Following a brief stint as a barista, Reese returns to the medical world as a psychiatrist-in-training under Dr. Daniel Charles (Oliver Platt) — a position she sticks with despite her creeping self-doubt. In fact, she grows to be quite good at her job, and Charles assures her the only place he sees her going is up. Their mentor-mentee relationship is as imperative to the show as any of the cases they tackle together.
When Reese's long-absent father returns to her life as one of Charles' patients, things take a turn for the worse. The emotionally manipulative man is soon diagnosed as a psychopath, and — worse — is discovered to be a serial killer. Charles decides to withhold that information from Reese, but it stays secret for only so long. Upset and disturbed by Charles' nondisclosure — not to mention the drama surrounding her father's psychopathy and subsequent heart attack — she ultimately leaves Gaffney Chicago Medical Center for good, striking out for a life far away in Texas.
