At the end of Flash Season 03, Barry Allen sacrificed himself to please the Speed Force and save Central City. This left Wally as the “Fastest Man Alive” and Team Flash reeling. At the start of Season 04, Kid Flash is taking over for Flash in a big way, and according to Candice Patton and Keiynan Lonsdale talked (who talked at SDCC about this according to Comic Book Resources) about how they will be different via a new dynamic.
“I think it’s a great dynamic, because now they get to work a little more closely together,” she noted. “Kid Flash has kind of had to step up to take over Barry’s shoes, and so now Wally and Iris are kind of co-workers, essentially. That kind of dynamic we saw in the Flashpoint episode, this brother-sister team up, which is really cool.”
“It only makes it stronger, I think. I think [Wally] definitely feels even more closer, especially to Iris, because he knows what she’s going through,” he explained, “Even if they may not talk about it, they can vibe each other. He’s really looking out for her best interests, so I think a lot of — even in a sense of being this team — he also knows how much that means to her, dealing with this whole loss of Barry.”
The Flash returns to CW on October 10th.