With a larger role in Season 4, Sneak Peek 'Killer Frost' in "The Flash" episode written by Judalina Neira, Andrew Kreisberg, Brooke Roberts and directed by Kevin Smith, that aired November 22, 2016 on The CW:
"...'Caitlin' (Danielle Panabaker) uses her powers to save 'Barry' (Grant Gustin) but as her mother predicted, the effort unleashes her inner 'Killer Frost'.
"Killer Frost goes on a rampage looking for 'Dr. Alchemy', kidnapping 'Julian' (Tom Felton) and battling both 'The Flash' and 'Vibe' (Carlos Valdes). Meanwhile, 'Joe' (Jesse L. Martin) and 'H.R.' (Tom Cavanagh) have a heart to heart talk..."
Click the images to enlarge and Sneak Peek "The Flash: Killer Frost"...