The Flash (Grant Gustin) teams up with Supergirl (Melissa Benoist), Arrow (Stephen Amell), and the Legends of Tomorrow to fight off a major invasion. Meanwhile, could Ronnie (Robie Amell) show up again in season 3?

The upcoming eighth episode of "The Flash" season 3 — titled "Invasion" — will feature a crossover among the different arcs in the Arrowverse. The episode is tied into the 100th episode of "Arrow" and features the coming of The Dominators, aliens who want to take over Earth.

According to the synopsis released by Den of Geek, The Dominators will first come to Central City, and Barry will visit Star City to ask for Oliver's/Arrow's help. But they soon realize that they need more heroes on the job, so they will track down the Legends of Tomorrow and create a breach to ask for Supergirl's assistance.

"Once all of the super friends are assembled, they come up with a plan to attack but a shocking secret related to Flashpoint is revealed and suddenly no one is sure who they can trust. Meanwhile, Wally (Keiynan Lonsdale) wants to join the battle against the aliens but Iris (Candice Patton) tells him he's not ready," the synopsis read.

According to CBR, EW reported that The Dominators are alien mind-controllers who will invade Earth because of the growing number of metahumans.

Meanwhile, could Ronnie come back to Caitlyn (Danielle Panabaker) in "The Flash" season 3?

Ronnie was killed in the series a total of three times, the other two times were when he was Firestorm and Deathstorm. However, Comicbook's Brandon Davis asked Amell if there is a chance that Ronnie could still come back to the show.

"Well the nice thing is when you're dead in that universe there is always another Earth, but I think that version of Ronnie is dead because he sacrificed himself to save the city, but you know there is always Earth-3, Earth-4, Earth-5," Amell teased.

"The Flash" season 3 airs every Tuesday at 8 p.m. EST on The CW.