<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 for six months, but refuses to grieve Barry . A flying samurai with superpowers appears in Central City, threatening to destroy 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' orders, Team Flash successfully returns Barry, who rambles random statements and continually writes symbols on the 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 an android . Caitlin rejoins Team Flash, but is revealed to have been working for a mobster called Amunet, while also continuing to prevent the Killer Frost personality from emerging . The "Samuroid" is revealed to have been controlled by the Thinker, 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> T27. 13402 </Td> <Td> 2.54 </Td> </Tr>

When did season 4 of the flash end