'The Flash' Season 1, Episode 3 Spoilers: The Mist He Can't Outrun, Plus 'The Tomorrow People' Alum Arrives [Watch The Flash 01x03 Promo Video]

IN PHOTO: Cast Member Grant Gustin Attends A Panel For The CW Television Series 'The Flash.' — IN PHOTO: Cast member Grant Gustin attends a panel for The CW television series "The Flash" during the Television Critics Association Cable Summer Press Tour in Beverly Hills, California July 18, 2014. MARIO ANZUONI/Reuters

"The Flash" Season 1, Episode 3, titled "Things You Can't Outrun," airs Tuesday, Oct. 21, on The CW. This week's new episode welcomes Robbie Amell, who played Stephen Jameson on the defunct CW series, "The Tomorrow People."

Spoiler alert: This update contains The Flash Season 1 spoilers. Read at your own risk if you have not watched the previous episodes or seen the 01x03 promo video.

Cisco dropping the name of Caitlin's late fiancée in The Flash Season 1, Episode 2 got some viewers wondering if they would ever meet Ronnie. The CW releases a synopsis that says he is showing up in this week's new episode:

"As Barry (Grant Gustin) and the team at S.T.A.R. Labs work to capture Kyle Nimbus (guest star Anthony Carrigan), a.k.a. The Mist, a dangerous new meta-human with toxic gas powers, they revisit the painful night the particle accelerator exploded and killed Caitlin's (Danielle Panabaker) fiancé, Ronnie (guest star Robbie Amell)."

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The same CW release spills the re-appearance of The Flash in the 90s TV, John Wesley Shipp. Watch the 1x3 promo video to catch a glimpse of The Mist.

"Meanwhile, Joe (Jesse Martin) decides to finally visit Henry (John Wesley Shipp) in jail after all these years, but things take a dangerous turn when Kyle shows up looking to punish Joe for arresting him years ago. Meanwhile, Iris (Candice Patton) and Eddie (Rick Cosnett) continue to hide their relationship from Joe. Jesse Warn directed the episode written by Alison Schapker [and] Grainne Godfree."

Spoiler alert, Amell's Ronnie Raymond, who is believed to have died in the S.T.A.R. Labs explosion, is the TV's "Firestorm." More characters from the DC comics universe are expected to arrive in the series, and there will be crossover episodes with "Arrow" Season 3, starring Robbie's cousin, Stephen Amell.

In The Flash Season 1, Episode 2, Dr. Harrison Wells (Tom Cavanagh) kills Simon Stagg because the Flash must be "safe." The same character closes the pilot episode by rising from his wheelchair. Viewers are guessing what he'd do next to cap the third episode of the series. More important, is he good, or evil?

WATCH: The Flash vs The Mist in Season 1, Episode 3 | The CW on YouTube