Barry confronts Savitar.
Barry: I know who you are.
Savitar: It's about time.
Flashback: 16 hours ago
Joe and Cecile are alone at the house.
Joe: Why haven't you given up on this New Year's resolution yet?
Cecile: I'm serious about running in the marathon.
Joe: I'm not running with you, are you mad?
Cecile: No, I love you too much to be mad.
They are now sitting in awkward silence.
Cecile: I'm sorry, I shouldn't have said that.
Joe: It's alright, Cecile wait, come back.
Cecile leaves.
Joe gets a call from Barry and heads to STAR Labs.
Joe: What is it?
Barry: Tracy Brand, my future self told me she's the key to stopping Savitar.
Iris: How?
Barry: My future self said she developed the technology that trapped Savitar in the speed force, but she didn't create it until four years ago from his perspective.
Iris: Four years after I die.
Barry: But luckily, my future self gave me the designs for the trap, so she might be able to read them and manage to build it.
Joe: Where is she?
Cisco: She is currently enrolled in CCU's theoretical physics program.
Barry: Cisco, call the Legends for backup.
Cisco: Can do.
Barry, Cisco, and HR arrive at Central City University.
HR: Hey, do you guys smell anything burning?
They walk into a room, they see Tracy Brand next to a fire and they put it out.
Tracy: What do you think you're doing?
Cisco: Saving you from a firey death?
Tracy: No, I'm just destroying my work.
Barry: Why?
Tracy: The university is no longer allowing me to work here.
Barry: What are you gonna do now?
Tracy: There's a job opening at Big Belly Burger.
Barry: You can't do that, the world needs your work.
Killer Frost makes an appearance.
Killer Frost: Admission here is way too easy.
She shoots an ice spike at Tracy and Barry saves her.
Killer Frost then knocks Barry out.
Cisco: So, you've gone full Killer Frost.
Killer Frost: I like these clothes way better than my old ones.
Cisco: I don't wanna hurt you, Caitlin.
Killer Frost: You won't.
Killer Frost blasted Cisco into a wall and Barry woke up and scared her off.
Barry: Cisco, are you okay?
Cisco: Yeah, let's go after Caitlin.
By the time they went after her, she was already gone.
Cisco: Well, I guess this means she's teamed up with Savitar.
They make their way to CCPD, Tracy is with a sketch artist.
Tracy: Wow, that looks exactly like her.
The sketch artist gave the drawing to Joe.
Barry: What are we gonna do?
Joe: I'm going to hide this sketch.
Tracy: Well, I'm going to Jitters and then home.
Barry: You should stay here, that meta could come after you again.
Tracy: It was just a random attack.
Tracy leaves.
Barry: I'm gonna have HR follow her.
In some unknown location.
Killer Frost: I wasn't able to kill her.
Savitar: You disappoint me.
Killer Frost: Barry and Cisco were already there.
Savitar: Yes, I told you about this before you left, maybe there's more Caitlin Snow inside you than you lead me to believe.
Killer Frost: She's gone.
Savitar: You call yourself Killer Frost, but you haven't killed anyone yet, kill the girl and we both could be gods, free from the pain of being human.
Killer Frost leaves.
Tracy and HR are at Jitters.
Barista: How will you be paying for the drink?
Tracy: I had a coupon, give me a minute.
HR: I will pay for her drink, whatever she wants, I'll have a Flash.
Tracy: I'll have a Zoom, extra cayenne. Hey, I know you, are you following me?
HR: Yes, me and my friends are interested in your research.
Tracy and HR sit down and they starts discussing her theories.
Tracy: I think that not all of the lightning we see coming from speedsters isn't entirely generated from them running, I think it comes from somewhere else, it's something else.
HR: Like a Speed Force?
Tracy: Yeah, great name for it, I think that we people could learn to harness it, even manipulate it.
HR: Like use it to make a prison?
Tracy: Yes, among other things.
When HR tried to drink his coffee, he noticed that it had frozen solid.
HR: We need to leave, now.
They get outside and another icicle is flying straight towards Tracy's head.
Barry comes in out of nowhere and saves her again.
Barry: Where are you Caitlin?
Killer Frost: Right here.
Barry: You don't have to do this.
Killer Frost: I know, but I want to.
Barry: Get Tracy out of here.
Killer Frost: You can't protect her from me.
She uses her powers to create an ice slide and chases after them, Barry follows.
Barry: Cisco, blast her!
Cisco: I can't!
Killer Frost: But I can.
She shoots and Barry takes the hit for Cisco. She approaches an injured Barry.
Killer Frost: Left leg last time, right?
Barry: Yeah, why... aaah!
Killer Frost: Scar tissue is very sensitive.
A sudden streak of fire scared her off and a girl dressed in white leather came to Barry's side to check on him.
Sara: Are you okay Barry?
Barry: I'll live.
Barry, Cisco, and the Legends head back to STAR Labs and tell Tracy Brand everything.
Tracy: So, I'm like Sarah Connor?
HR: More like Miles Dyson, nice try though.
Sara: More importantly, why was your friend trying to kill you?
Cisco: Ask Draco Malfoy over there.
Julian: I did it to save her life, you have no room to talk, you've had many chances to take her down, if you did, she'd be here and Barry wouldn't be hurt!
Barry: Guys, enough.
Barry turns his attention to the Legends.
Barry: Thanks for showing up when you did.
Sara: No problem, you called at just the right time, any idea who this Savitar is and why he hates you so much?
Barry: No, all I know is that he's from the future, he knows very much about the timeline, and he knows everything there is to know about us.
Sara: Well, we're here to help.
Back at Joe's house, he has a talk with Cecile.
Cecile: I understand if you aren't at the same place in the relationship as I am.
Joe: It's not about that, there's just too much going on right now, we can't be together, it's just too complicated.
She starts to cry.
Cecile: Okay, see you at work Joe.
She leaves, a minute later, he hears a knock on the door and opens it to see Cecile with an icicle pressed against her throat.
Joe: Caitlin, please don't do this.
Killer Frost: Tell The Flash to bring me Tracy Brand, otherwise, the next time you see her, it will be with an icicle in her throat.
She then blasts him into the wall.
After thirty minutes everyone, including the Legends, tracked her back to a wearhouse.
Tracy: Why do you want to kill me?
Killer Frost: The main reason is to prevent you from making Savitar's prison, but Savitar said there was another reason he wants you dead, a very personal one.
Barry: Caitlin, don't do this.
Killer Frost: Why?
Barry: Because...
Both: We're family. We love each other. We protect each other, till the very end.
Barry: How did you do that?
Killer Frost: Savitar told me what you'd say, he's very thorough, he knows way more about you than I thought, which is how I know that Cisco is up in the rafters right now.
She detonates an explosive, Cisco falls into some cardboard boxes, laying unconscious.
The Legends decided to hide at first and listen, but after seeing what happened, they joined in the fight.
Ray: That was starting to get scary.
Killer Frost: About time you got here, stay back, or she dies.
A vibrational burst came out of nowhere and knocks her unconscious.
Cisco: Sorry Caitlin, but I'm doing this to save you.
He takes out a needle and acquires her blood, but then the room is consumed in white lightning, Cisco is knocked a few feet away from Killer Frost, and Savitar appears.
Savitar: My ascension is at hand Barry, when I rise, you shall fall.
Ray: Good thing he isn't alone.
Savitar: So Barry, you finally called these so-called "Legends" for help.
Ray: How did you know we'd be here?
Savitar: Because Raymond, I know everything there is to know about you, I know your fears, I know your weaknesses, I know that no matter what you do, you will never be remembered, any of you!
Sara: How do you know all of this?
Savitar: I've walked among you heroes, assassin.
With that, he took Killer Frost and left.
Everyone went back to STAR Labs.
Ray: What did he mean when he said "I've walked among you?"
Sara: He meant that he is someone we've met, someone we know.
Barry noticed that Mick was more quiet than usual and Barry told Mick that they needed to have a conversation, in private.
Barry: There's something wrong with you, what is it?
Mick: For a little while, I saw Snart, he was telling me to leave the team and help bring him back.
Barry: When did you first see him?
Mick: Six months ago, but I haven't seen him in awhile.
Barry: When did the hallucinations stop?
Mick: A little over two months ago, why?
Barry started to figure everything out, but he needed one more person to confirm his suspicions.
Barry: Ray, how did Snart die, exactly?
Ray told him everything, the Time Masters, the Oculus, everything, and as soon as Ray finished his sentence, Barry raced out of the building.
Ray: Barry!
Barry: I'm here, come out and face me!
Savitar appears.
Flashback ends.
Barry: Everything is about time with you, isn't it? The past, the present, the future. You know all of it, right? You know our strengths, you know our fears, you know how much we love each other, and you know how to use that love against us, you know all of this because you've interacted with us, you were a friend.
The back of the armor opened up to reveal the face of someone he's known for a long time, Leonard Snart.
Barry: Snart.
Snart: Hello Barry, it's been a long time.
Barry: Why?
Snart: Why? You know why, Barry. The Speed Force was trying to warn you when it started talking about me, it told you my motive.
Barry: How?
Snart: Now, that is one hell of a story, Barry...
TBC
The next chapter will pick where this one left off.