Season synopsis
Contains spoilers for this season and earlier seasons.
After six months without Barry in Central City, Cisco and Caitlin find a way to bring him back from the Speed Force. He returns confused and speaking in fragments, but comes out of it when Iris puts herself in danger during an attack by a mechanical samurai. The team traces that threat to a plan by Clifford DeVoe, a brilliant adversary called the Thinker, whose wife Marlize helps him target the city. Barry and Iris resume their life together while the team learns DeVoe has prepared a much larger campaign.
DeVoe’s plan depends on stealing the abilities of passengers transformed by the dark-matter wave released when Barry returned, and he moves his consciousness through other bodies as he gathers their powers. Ralph Dibny, the Elongated Man, becomes one of those hosts. The Thinker launches five satellites to trigger the Enlightenment, an electromagnetic pulse that would disrupt technology while his intended broadcast strips people of independent thought. Iris reaches Marlize and persuades her to turn against her husband, while Barry, Cisco and Caitlin coordinate to rescue hostages and try to stop the launch.
When the Enlightenment begins, Marlize helps send Barry into DeVoe’s mind to find the good person she once loved. Barry discovers Ralph there and helps him fight his way back into his own body; together they defeat DeVoe’s mental copies. DeVoe’s backup plan still sends the satellite crashing toward Central City, and Barry destroys it with help from an unseen speedster. Team Flash welcomes Joe and Cecile’s newborn Jenna, then meets Nora, who says she is Barry and Iris’s daughter from the future and has made a serious mistake.