Chloe moves in New York's most elite circles with her lawyer husband Adam and teenage son Ethan by her side while her estranged sister Nicky tries to make ends meet and stay clean. When Adam is brutally murdered, the investigation sends shockwaves through the family and exposes long-buried secrets.

Central City Police forensic scientist Barry Allen's crime lab is struck by lightning. Allen's electrified body is flung into and shatters a cabinet of chemicals, which are both electrified and forced to interact with each other and with his physiology when they come into physical contact with his body. He soon discovers that the accident has changed his body's metabolism and as a result he has gained the ability to move at superhuman speed. Barry Allen has become the Flash.