The Flash has zoomed to San Diego for this year's Comic-Con International. Stars Grant Gustin, Carlos Valdes, Candice Patton, Jesse L. Martin, Kieynan Lonsdale, Danielle Panabaker, Tom Cavanagh and executive producer Todd Helbing were on hand to reveal more details about the upcoming Season 4.

The panel opened with a sizzle reel for Season 4. Candice Patton's Iris West narrated in place of Barry and revealed a changed Team Flash, who soldiers on in Barry's memory. Iris seemed to take a lead role in the proceedings. Panabaker's character also appeared, though not with white hair per Killer Frost.

"It's so much more fun to bad," Panabaker said. As to her character's direction, she said, "No one is going to be disappointed."

"There's a thousand different Wells," Cavanagh shared. He added that there's probably "a thousand more" that the show could explore.

As to Joe West's love life, Martin said, "Apparently, we're going to get a little bit more serious. That's really I can say."

"Jessica Camacho... she showed up, and I didn't know what this was going to be like... because it's supposed to be a romance... Instantly, we hit it off," Valdes shared. "She really got the material. She really committed to the character... I'm looking forward to doing a lot more of that."

Danny Trejo will play Gypsy's father Breacher. The 100's Neil Sandilands will play The Thinker. Kim Engelbrecht will appear as The Mechanic.

And how did Valdes react to the news of Trejo's casting? "I pooped my pants," he said.

"It's the fastest man alive verses the fasted mind alive," Helbing explained. "We're really trying to lighten the tone a lot... We want to get back to the jokes."

"The whole team had to come together and be like, 'How we make this work... without the guy who was our lead?'" Lonsdale shared. "I think they're just trying to be there for each other to navigate this situation."

"For me, Iris, she's devastated that he's gone into the Speed Force and that they didn't really have a discussion about it," Patton revealed. "We pick up Season 4, Iris has set her focus on being the lead of Team Flash."

Asked if Iris will play a role in breaking Barry out of the Speed Force, Patton said, "Yeah, to a degree. I'd say so. She's kind of boss lady at Team Flash, so she's an active participant in getting her man back."

"Right now, we don't have any plans," Helbing said when asked if there would be another musical episode.

One fan asked for clarification about how Savitar was able to exist. "There's a reason why we're not doing time travel anymore in Season 4," Helbing responded.

"We like to pull from all the characters from the comic books. There's a whole list of people we'd like to pull from," Helbing said when asked if Johnny Quick could show up on the series.

Returning Tuesday, Oct. 10, at 8 p.m. ET/PT on The CW, The Flash stars stars Grant Gustin, Candice Patton, Danielle Panabaker, Carlos Valdes, Tom Cavanagh, Jesse L. Martin and Keiynan Lonsdale.