<P> The Flash is an American 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 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 . </P> <P> 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 . Colleen Atwood, costume designer for Arrow, was brought in to design the Flash's suit . The creative team wanted to make sure that the Flash would resemble his comic book counterpart, and not simply be a poor imitation . The series is primarily filmed in Vancouver, British Columbia, Canada . </P> <P> The Flash premiered in North America on October 7, 2014, where the pilot became the second-most watched premiere in the history of The CW, after The Vampire Diaries in 2009 . It has been well received by critics and audiences, and won the People's Choice Award for "Favorite New TV Drama" in 2014 . The series, together with Arrow, has spun characters out to their own show, Legends of Tomorrow, which premiered on January 21, 2016 . On January 8, 2017, The CW renewed the show for a fourth season, which is scheduled to debut on October 10, 2017 . </P> <P> After witnessing his mother's supernatural murder, Barry Allen is taken in by Detective Joe West and his family . Barry becomes a brilliant but socially awkward crime scene investigator for the Central City Police Department . A particle accelerator malfunctions, bathing the city center with a radiation during a thunderstorm, and Barry is struck by lightning . Awakening after a coma, he discovers he can move at superhuman speeds . Harrison Wells, the accelerator's designer, describes Barry's nature as "metahuman". Barry vows to use his gifts to protect Central City . As the Flash, Barry also pursues his mother's murderer, the Reverse - Flash . </P>

When did the tv series the flash start