In some photos from the upcoming Flash episode Girls Night Out, we see that it include Iris (Candice Patton), Caitlin (Danielle Panabaker), Felicity (Emily Bett Rickards) and Cecile (Danielle Nicolet). It's a good sign that Iris and Cecile are getting along well, as when a dad gets a new girlfriend, sometimes they don't quite connect well with the daughter. And while there is no problem with Cecile dating Joe (Jesse L. Martin), there does seem to be some kind of problem between Iris and Cecile.
Candice Patton talked about the relationship with EW.com:
"They have their own interpersonal relationship drama that will go down this season. Iris really respects Cecile. I think she knows how much Cecile makes her dad happy, so in Iris' eyes, she's a welcome addition to the family. You'll just have to wait and see how that whole thing between them plays out."
Cecile was let into the club when Joe sat down and told her about Barry (Grant Gustin) being the Flash. This could be an odd sticking point, since Cecile is a prosecutor — and if the identity of the Flash ever becomes an issue in a case, it could lead to some interesting moral questions on her part.
The Flash Season 4 debuts October 10th at 8 p.m. ET on the CW.