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. The first season follows crime-scene investigator Barry Allen who gains super-human speed after the explosion of the S.T.A.R. Labs' particle accelerator. The series, together with Arrow, has spun characters out to their own show, Legends of Tomorrow, which premiered on January 21, 2016.