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 investi