The Flash gets blasted with a shockwave forcing his body to age prematurely.

Barry creates a map book to guide him and Iris throughout their future in order to keep her safe, but the results are not what he expected, and instead, they relive the same day over and over again. Joe has a heart-to-heart with Cecile. A new big bad is introduced to Team Flash and friends and foes, old and new, begin to descend upon Central City.

The Flash is forced to make an impossible choice. With the power out in the city, Team Flash calls upon the Rogue Squad to help as Iris is visited by an old friend. Joe and Cecile work on finding a balance.