Chastain plays a hospital nurse who suspects her friend and colleague (played by Redmayne) is intentionally killing patients in Tobias Lindholm's film.
Chastain’s Amy, a single mother, spends her time caring for others while trying to hide her own ailment: She has a heart disease that causes frequent episodes of difficulty breathing; her doctor says she’s at risk of dying soon from it, unless she gets a transplant. But despite working in a hospital, she’s still several months away from qualifying for work insurance. Paying for a transplant is inconceivable unless she manages to stay on the job, regardless of the pain and stress it causes.
But when one of the elderly patients on their floor dies, hospital administrators quickly close ranks, seeming to know they have something big to hide even if they’re not certain what it is. Seven weeks after the death, the company’s risk officer is forced to alert police to the unexplained event, but keeps using internal investigations as an excuse not to tell them everything she knows.
While Lindholm monitors the coworkers’ friendship, Krysty Wilson-Cairns’ screenplay efficiently uses procedural scenes to uncover a rot in this and other for-profit hospitals’ liability-reduction strategies. Since acknowledging their suspicions about Charlie would open the door to wrongful-death lawsuits and maybe more, previous employers would simply fire him quietly, never saying why and never acknowledging any problem to outsiders like other prospective employers.