Ollie Cross (Tye Sheridan) is a young med student who, as a way of gaining both money and experience, signs up to work as a paramedic during the night shift in New York City. Paired with the seasoned but haunted Gene "Rut" Rutkovsky (Sean Penn), and as the pair respond to 911 call after 911 call, the idealistic young Mid-Westerner is forced to confront the very worst human suffering imaginable in a city that seems forever on the brink of utter devastation.