This week on "The Flash," Wally (Keiynan Lonsdale) began dreaming about being Kid Flash as Doctor Alchemy set his sights on him, while Caitlin (Danielle Panabaker) came clean about her powers.

Wally told Joe (Jesse L. Martin) that he had been having dreams about being Kid Flash, and this made his father worried as the same thing happened to Magenta (Joey King) when Alchemy was trying to control her. When Joe proved to be right, Wally agreed to get locked up in the pipeline until Barry (Grant Gustin) and the team could figure out what to do about the villain.

Meanwhile, Caitlin stole some power-dampening cuffs from Cisco (Carlos Valdes), and when he noticed, she was forced to admit that she has powers. When Caitlin asked him to vibe and see if she's turning into Killer Frost, Cisco saw himself fighting a meaner version of his friend in the forest, and when he told her about it, Caitlin decided to leave.

At S.T.A.R. Labs, Cisco forced Caitlin to tell everyone about her powers, and Barry said that it was his fault because he changed the timeline. Later, the team decided to use Wally as bait to get Alchemy, and they had the entire S.W.A.T. team as backup. They were able to surround Alchemy, and just as Barry was about to unmask the villain, a blue streak started zooming around the room and killing members of the S.W.A.T. team. Towards the end of the episode, Barry found himself in the tight grip of Savitar, the god of speed.

Next week, in the episode titled "Killer Frost," Caitlin uses her powers to save Barry, but as her mother predicted, the effort unleashes her inner villain. Killer Frost goes on a rampage looking for Dr. Alchemy, kidnapping Julian (Tom Felton), and battling both The Flash and Vibe. Elsewhere in the episode directed by Kevin Smith, Joe and H.R. (Tom Cavanagh) have a heart-to-heart talk.

In the promo for "Killer Frost," Caitlin says that the villain is inside her and is angry, and later, Killer Frost and Vibe are seen fighting it out on the street. She is seen showing off her powers to Julian, and once he has been rescued, the CSI investigator tells Barry that Caitlin is "a meta, and not one of the friendly ones."

Barry defends his friend and says that she's sick. When Julian urges The Flash to knock her out, the Brit gets a punch in the face instead. Barry asks Caitlin what she's doing, and she blames him for making her cold-hearted.

"The Flash" airs Tuesdays at 8 p.m. ET on The CW.