Episode 25

The doctors of Grey Sloan Memorial Hospital deal with life-or-death consequences on a daily basis -- it's in one another that they find comfort, friendship and, at times, more than friendship. Together they're discovering that neither medicine nor relationships can be defined in black and white. Real life only comes in shades of grey.

9-1-1: Lone Star follows a sophisticated New York firefighter who, along with his son, relocates to Austin, and must try to balance saving those who are at their most vulnerable with solving the problems in his own life.

9-1-1 is a fast-paced exploration into the lives and careers of first responders – cops, paramedics, firefighters – the people who put their lives on the line to save others.

Earth is visited by an alien species that threatens humanity's existence. Events unfold in real time through the eyes of five ordinary people across the globe as they struggle to make sense of the chaos unraveling around them.

NOVA brings you stories from the frontlines of science and engineering, answering the big questions of today and tomorrow, from how our ancestors lived, to whether parallel universes exist, to how technology will transform our lives.