The heart of the season is Jean’s obsession with , the manipulative and magnetic ex-girlfriend of one of her patients. As "Diane," Jean begins a pulse-pounding affair with Sidney that threatens to shatter her suburban life with her husband, Michael. The deeper she sinks into Sidney’s world of dive bars and secrets, the more the mask of the "perfect therapist" slips.

Season 1 follows Jean as she crosses the ultimate professional line, infiltrating the personal lives of the people her patients complain about. She doesn't just listen to stories of toxic exes and overbearing mothers—she tracks them down, befriends them, and inserts herself into their reality.

In the shadowy, high-end offices of Manhattan, plays a dangerous game. To her patients, she is a composed, empathetic therapist; to the strangers she stalks, she is "Diane Hart," a woman unburdened by a wedding ring or a conscience.

By the finale, the boundaries between Jean’s two lives have completely eroded. She is caught in a web of her own lies, realizing that while she was busy playing God with her patients' lives, she may have been the one being played all along.