The Flash is an American superhero television series developed by Greg Berlanti , Andrew Kreisberg , and Geoff Johns , airing on The CW . It is based on the DC Comics character Barry Allen / Flash , a costumed superhero crime-fighter with the power to move at superhuman speeds. It is a spin-off from Arrow , existing in the same fictional universe . The series follows Barry Allen , portrayed by Grant Gustin , a crime scene investigator who gains super-human speed, which he uses to fight criminals, including others who have also gained superhuman abilities. Initially envisioned as a backdoor pilot , the positive reception Gustin received during two appearances as Barry on Arrow led to executives choosing to develop a full pilot to make use of a larger budget and help flesh out Barry's world in more detail. The series is primarily filmed in Vancouver, British Columb...