At TCA, executive producer Andrew Kreisberg offered more details about the upcoming seasons of "Arrow," "The Flash," "Supergirl" and "Legends of Tomorrow" during an interview with The Hollywood Reporter.

Of "The Flash," Kreisberg revealed, "We're working on episode four, which is exciting, [and] there is a flashback to the night of the particle accelerator explosion, from somebody else's perspective which we haven't seen before. It's a good one."

He also weighed in on how both "Arrow" and "The Flash" would lead into "Legends of Tomorrow," saying, "Both 'Arrow' and 'Flash' are helping to set those things up, in both big ways and small ways, which is lovely... The mystery of what happened with Palmer (Brandon Routh) is playing out on 'Arrow.' Sara Lance (Caity Lotz) will also be playing out in the first seven episodes. 'The Flash,' we obviously have Firestorm and Martin Stein (Victor Garber) and Ronnie Raymond (Robbie Amell). And Kendra Saunders (Ciara Renee) lives in Central City in the Flash finale. Getting to know her. There's going to be a lot happening leading up to the crossover, which is serving as a [quasi] pilot for Legends."

"Arrow" will have a particularly big role to play in Sara's revival, with Kreisberg citing a resurrection that will happen in the episode featuring John Constantine (Matt Ryan). "I just read the script for five and it's unbelievable," he shared. "You're going to be blown away."

He also revealed a little more about Superman's role in "Supergirl," explaining, "There was originally a flashback sequence [with] Dean Cain and [former movie Supergirl] Helen Slater, and a much longer scene where he's talking about Superman... It's one of my favorite moments of shooting the pilot was seeing Dean Cain talk about Superman. It just kept making me gush. But with the third episode coming out, it's very much about Superman's place in the world, and Kara's place in the world, and why isn't Superman going to be on our show every week. That episode has a lot of discussion about him."

"They are on different networks, they are separated, but the stories Greg [Berlanit] and I like to tell, there's obviously a symmetry," Kreisberg said of all four shows. "Hopefully if you're a fan of 'Flash' and 'Arrow,' you'll be a fan of 'Supergirl,' and if you like 'Supergirl,' you'll check out 'Flash' and 'Arrow.'"

On The CW, "The Flash" premieres Tuesday, October 6 at 8 p.m and "Arrow" debuts Wednesday, October 7 at 8 p.m. "Supergirl" premieres Monday, October 26 at 8:30 p.m. on CBS. "Legends of Tomorrow" will have a midseason premiere on The CW.