<P> The fourth season of the American television series The Flash, which is based on the DC Comics character Barry Allen / Flash, follows a crime scene investigator with superhuman speed who fights criminals, including others who have also gained superhuman abilities . It is set in the Arrowverse, sharing continuity with the other television series of the universe, and is a spin - off of Arrow . The season is produced by Berlanti Productions, Warner Bros. Television, and DC Entertainment, with Andrew Kreisberg and Todd Helbing serving as showrunners . </P> <P> The season was ordered in January 2017, and filming began that July . Grant Gustin stars as Barry, with principal cast members Candice Patton, Danielle Panabaker, Carlos Valdes, Keiynan Lonsdale, Tom Cavanagh, and Jesse L. Martin also returning from previous seasons, and are joined by Neil Sandilands . </P> <P> The fourth season began airing on October 10, 2017, on The CW . </P> <Table> <Tr> <Th> No . overall </Th> <Th> No. in season </Th> <Th> Title </Th> <Th> Directed by </Th> <Th> Written by </Th> <Th> Original air date </Th> <Th> Prod . code </Th> <Th> U.S. viewers (millions) </Th> </Tr> <Tr> <Th> 70 </Th> <Td> </Td> <Td> "The Flash Reborn" </Td> <Td> Glen Winter </Td> <Td> Story by: Andrew Kreisberg Teleplay by: Todd Helbing & Eric Wallace </Td> <Td> October 10, 2017 (2017 - 10 - 10) </Td> <Td> T27. 13401 </Td> <Td> 2.84 </Td> </Tr> <Tr> <Td_colspan="8"> Iris has been aiding Team Flash in Central City, but refusing to grieve Barry . A flying Samurai with superpowers appears in Central City, threatening the city if the real Flash does not face him . Cisco reveals he has formulated a way to bring back Barry without destabilizing the Speed Force, and tracks down Caitlin for help . Against Iris' direction, Team Flash successfully returns Barry, who appears rambling random statements and continually writing symbols on walls . Wally engages the Samurai, but is defeated . Cisco deciphers Barry's writings and finds an apparently meaningless sentence . In an attempt to recover Barry's memories, Iris gives herself up to the Samurai . The plan works and Barry speeds away, rescuing Iris and defeating the Samurai, who is revealed to be a robot . Caitlin rejoins Team Flash, but is revealed to have been working for a mobster called the Amunet at the bar, also revealing she continues to have to fight the Killer Frost personality from emerging . The "Samuroid" is revealed to have been controlled by an unidentified man, whose plan was to draw out the Flash for his next schemes . </Td> </Tr> <Tr> <Th> 71 </Th> <Td> </Td> <Td> "Mixed Signals" </Td> <Td> Alexandra La Roche </Td> <Td> Jonathan Butler & Gabriel Garza </Td> <Td> October 17, 2017 (2017 - 10 - 17) </Td> <Td> TBA </Td> <Td> TBD </Td> </Tr> <Tr> <Th> 72 </Th> <Td> </Td> <Td> "Luck Be a Lady" </Td> <Td> Armen V. Kevorkian </Td> <Td> Sam Chalsen & Judalina Neira </Td> <Td> October 24, 2017 (2017 - 10 - 24) </Td> <Td> TBA </Td> <Td> TBD </Td> </Tr> <Tr> <Th> 73 </Th> <Td> </Td> <Td> TBA </Td> <Td> Tom Cavanagh </Td> <Td> TBA </Td> <Td> TBA </Td> <Td> TBA </Td> <Td> TBD </Td> </Tr> <Tr> <Th> 74 </Th> <Td> 5 </Td> <Td> "Girls Night Out" </Td> <Td> Laura Belsey </Td> <Td> TBA </Td> <Td> TBA </Td> <Td> TBA </Td> <Td> TBD </Td> </Tr> </Table>

When does series 4 of the flash start