Warning: The following contains spoilers for tonight's episode of The Flash, "Girls Night Out."
It hasn't been an easy life for Caitlin Snow (Danielle Panabaker). Since gaining her powers in the third season of The Flash, she's always been caught in the push and pull between being a good woman and embracing the inner demon that comes with her cryogenic powers.
When she first shows up at the start of the new season, it looks like Caitlin is back in control... until Frost comes out, demanding that meta-human dealer Amunet (Katee Sackhoff) leave her alone. But that's easier said than done, considering that Caitlin was once Amunet's muscle in exchange for a cure to her more trigger happy persona. During the times where Frost has taken control, she hasn't really lived up to her "Killer" moniker -- just some frozen fingers and toes for her unfortunate victims.
In subsequent episodes, her Frosty persona has threatened to break through and take complete control of her. By the time Iris is throwing her bachelorette party, Caitlin's making plans to skip town to avoid Amunet's wrath. When her enforcer Norvock shows up to crash the party, Caitlin transforms into Frost and lets it go. Iris (Candice Patton), Felicity (Emily Bett Rickards), and Cecille (Danielle Nicolet) are forced into the position of stopping Frost from trying to kill Amunet while also foiling Amunet's plan involving a metahuman whose tears work as a drug -- he's later referred to as The Weeper.
Frost is running scared throughout the whole episode, simultaneously afraid of both Amunet and being trapped in the prison that is Caitlin. It's only after Iris confronts her about her fears that the cryomancer decides to embrace both sides of herself -- Caitlin Snow and Killer Frost. Though Amunet promises her revenge someday, the internal battle for Caitlin has finally been won.
Starring Grant Gustin as the Scarlet Speedster, The Flash airs Tuesdays at 8 p.m. ET/PT on The CW. The series also stars Jesse L. Martin, Tom Cavanagh, Carlos Valdes, Candice Patton, Danielle Panabaker, Keiynan Lonsdale and more.