The Flash: Nora West-Allen will return for the show's 150th episode
Fans last saw the daughter of Barry and Iris West-Allen back in Season 5 (though she's been mentioned and reference a few times since then), when she arrived from the future to help Team Flash take on Eobard Thawne. However, when she and her father zoom into the future to help battle the villain in the season finale, she started to fade away. Eventually, they realised the destruction of big bad Cicada's dagger (which had been an artifact still around in Nora's future) had resulted in a new timeline, with the one Nora was from no longer in existence, causing her to be erased as well. Nora ul...
Source: syfy.com