艾米（杰西卡·查斯坦饰）是一名富有同情心的护士和单亲母亲，她正与危及生命的心脏病作斗争，她在重症监护病房上夜班，工作繁重，要求很高，身体和情绪都已达到极限。但当查理（埃迪·雷德梅恩饰），一位体贴而富有同情心的新护士来到她的病房时，帮助到来了。在医院度过漫长的夜晚时，两人建立了牢固 而忠诚的友谊，多年来，艾米第一次对自己和女儿的未来充满信心。但是，在一系列神秘的病人死亡事件引发了一项调查，指出查理是主要嫌疑人之后，艾米被迫冒着生命危险和孩子的安全来揭露真相。
Amy, a compassionate nurse and single mother struggling with a life-threatening heart condition, is stretched to her physical and emotional limits by the hard and demanding night shifts at the ICU. But help arrives when Charlie, a thoughtful and empathetic fellow nurse, starts at her unit. While sharing long nights at the hospital, the two develop a strong and devoted friendship, and for the first time in years, Amy truly has faith in her and her young daughters' future. But after a series of mysterious patient deaths sets off an investigation that points to Charlie as the prime suspect, Amy is forced to risk her life and the safety of her children to uncover the truth.
Single mother Amy (Jessica Chastain) is an ICU nurse struggling to keep her life on track while dealing with her own health issues. A new nurse arrives on her shift Charles Cullen (Eddie Redmayne) and the two begin a strong friendship as Amy trusts him with her health secret and he becomes a main support in her life. All the while, the death rate among ICU patients is up and an investigation ensues. Soon Amy suspects Charles is the culprit and she must work to ensure no more of her patients die while concealing her part in catching him. Based on a real-life story, Redmayne gives a chilling performance as Cullen, a serial killer whose total victim count remains unknown.
