It's the little things Caitlin notices first.

In a way it's kind of ironic, considering she noticed it first in Barry when he was pining for Iris. It seems fitting, she supposes, that she would start to notice those things in herself next - the way she would flit between keeping her distance from Iris at some points and sharing, maybe oversharing, at others; the way she would find herself smiling every time Iris spoke (because by God was it difficult to work with mostly men every day); and, perhaps, most of all, the chills that went up her spine every time Iris so much as smiled at her.

And at first she wondered if Iris West just had that effect on everyone - of being this good and wholesome and kind person who also wouldn't take shit from anyone. After all, Caitlin's liked girls in the past, but platonically, or superficially.

(It's never been like this.)

"You okay, Caitlin?" Iris asks in the lab one night.

Caitlin nods. "Yeah. Just thinking."

"About what?" says Iris, but then she holds up her hand and says into the speaker, "Babe, heat signatures are telling me you've got ten hostiles incoming from the southeast exit and four more around the corner from them."

"I got it, thanks," Barry replies on the comms.

Iris is still waiting expectantly, though, looking at Caitlin, who realises she hasn't answered the question.

"Honestly? Sometimes I wonder if I actually deserve to be here."

"Because of what Killer Frost did? Caitlin, you apologised already. To me, to Cecile, to Cisco, Barry -"

"It'll never be enough."

But Iris surprises her by reaching over and covering Caitlin's hand with her own. "Hey," she says softly, "it wasn't you. I know that. Hang on -"

"You there, Iris?" Barry says in the comms.

"Yeah, what's your status, Flash?"

"Hostiles are secure, but I've got to get a security guard to the hospital with a GSW to the leg. He should be okay, but I'm gonna run him there anyway."

"Keep it elevated, Barry," Caitlin says into the speaker. "And we'll -"

"- get CCPD to the scene," Iris says quickly. "And when you're done, there's a mugging in progress on Fifth Street. Get going."

"Yes, boss," Barry says, and Caitlin can't help but laugh at that.

"I guess someone has gotten used to you telling him what to do, huh?" Caitlin says.

Iris shakes her head. "He's always been used to it. Just not in public, right, babe?" she says playfully into the speaker.

There's a scuffling sound and then a loud punch. "Really, honey?" Barry says, and it's obvious he's trying to sound annoyed, but his tone is tinged with amusement.

"It's okay, Joe isn't listening in or anything," Caitlin assures him.

"Thank God for that," Barry says.

"All right, you can call it a night if you like and let Cisco take over, but I gotta sort out your next training simulation before I get home," Iris says, and the monitor in front of her does indeed have a half-finished training regimen on it.

"Got it."

His comm goes offline, and it's then that Iris turns to Caitlin once more with a purposeful look on her face and Caitlin's shoulders sink.

"As we were saying... when it came down to it, you didn't kill anyone."

"I still hurt people. I still threatened to harm people. I just -" And she doesn't expect it but tears spurt from her eyes all of a sudden and she forces herself to get to her feet, out of the chair and away from Iris. "I don't know how you can look at me and not see the person who helped a man try to murder you."

Behind her, though, Caitlin can hear Iris get up too and place a tentative hand on Caitlin's shoulder. Slowly, reluctantly, Caitlin turns around so she's facing Iris again.

"So you're probably wondering - why did I stay with Barry, knowing Savitar had Barry's face?" Iris says.

"It's different with you guys. He's loved you since you two were kids," Caitlin says simply.

And of course Iris's eyes light up at that.

"Yeah, and I've loved him. For… at least half my life."

"It would be strange if you let that go just because -"

"- his evil future self was trying to kill me and become some kind of god?" Iris says, and it's with the tired kind of smile that makes Caitlin want to hug her.

(They've never hugged. The three years they've been in each other's lives, however intermittently, Caitlin's never put her arms around Iris and held her close. No. That's always been Barry's job.)

"It wasn't really him, though. Savitar was only a time remnant."

"And I can't explain the science behind why you were a different person with your powers," Iris says. "But what I can say is that Savitar had all of Barry's memories. His thoughts. He was a lot like Barry. His actions didn't mean that I loved my Barry any less."

Maybe it's because it's late, early, whatever, or because she can sense Killer Frost growing restless inside her. "Okay. How does that relate to me, exactly?"

"I'm saying, if I could keep on loving Barry after… everything that happened, then I think it's definitely possible to have a little more love for yourself."

Caitlin tilts her head slightly to one side, feeling a slow smile spread on her face. "You think so?"

"I know so," Iris says firmly. "Even if you think it was you and not Killer Frost - either way, I forgive you. And I'm telling you now, as leader of Team Flash, you have every right to be here."

"Thanks, Iris."

Iris smiles back. "Anytime."

And for a moment Caitlin wonders - for one glorious moment - if there is any way she could tell Iris, about what's been happening with her, with Killer Frost, since she's been back on Team Flash.

But try as she might, she can't get the words out to save her life. And the voice of Killer Frost is loud in her ears - it's not like she'll see you as anything but the monster you were.

Eyebrows raised, Iris is watching her, and Caitlin, cold as she is, feels almost burned by her gaze, so she quickly says the first thing she can think of. "So, uh, did you finally decide on a wedding dress?"

To Caitlin's relief Iris chuckles. "Girl, I have gotten through way too many and none of them look right."

"You'll find the right one," Caitlin tells her. "You'll just know it when you see it, trust me."

"I remember your wedding. You looked beautiful."

Caitlin flushes and has to tear her eyes away hastily. "Thank you, but -"

"Seriously. It's so hard to pull off strapless, but you have the right figure for it."

"I'm, uh, glad you were there," Caitlin says quietly. "I know we didn't really know each other back then - but you did save my life. There's no one I'd rather have had by my side than you."

"Thank you," Iris says sincerely. She looks like she's about to say something, but then she seems to think better of it.

"What's up?" Caitlin asks.

At first Iris hesitates. Then she says, "I feel - I know it's ridiculous, but because Barry's seen me in two dresses, now, I feel like maybe something will go wrong."

"Like what? And please don't say jilting you at the altar, because that boy has been ready to marry you since he was twelve - and those are his words, not mine."

Iris doesn't even seem surprised, though - if anything she just smiles sheepishly. "Actually, we, er, may or may not have gotten married when we were twelve. With, uh, I think it was a toy dinosaur as our officiate? I'm pretty sure her name was Gertrude."

And it's only then that Caitlin realises how much her heart is aching, because Iris recalls the memory so fondly, and it hits her then how Caitlin's never really had that with anyone she grew up with. No one she got pretend-married with. No one she had a history with.

"Aw," she says, and she does mean it, even if there's more than a touch of yearning in her voice that she can't keep out. "That's adorable."

"I know. Dad got the whole thing on camera, too. And yeah, I know. He's not gonna run - even if he is the Flash. But I totally fall for all that bad luck stuff. And we've just had so many bad things happen."

"Maybe they will," Caitlin says. "But you - you deserve to be happy. And you can't not take that chance just because your life is a little…"

"...exciting?" Iris suggests dryly.

"I was gonna go with 'chaotic', but yeah, that too. My point is - sometimes you gotta close your eyes and jump."

"And what if I fall?"

"There's nothing wrong with falling." Caitlin pauses for a moment. "Even if you didn't have the Flash to catch you."

"What do you mean?" Iris asks.

"I mean - you've always been strong, Iris. But Cisco told me how when Barry went into the Speedforce you took charge. You learned your stuff, you helped train Wally, you kept it together."

Iris half-laughs at this, shaking her head. "No way. If Cisco felt like I had it together it's only because I put on a front for everyone. When… when it was just me, there were days. Days where I would cry myself to sleep."

"I know what that's like," Caitlin says sympathetically.

"Times like that were the worst. And it was strange, really strange, because I couldn't talk to Wally or Dad or Cisco. They needed Iris the leader. But during those times... I found myself wishing I could talk to Francine."

"Your mom?"

Iris sighs. "Yeah. Before - before she died, we talked. About what could have been for us. And I just remember that she was a good listener. And that's what I needed."

"I'm sorry," Caitlin says softly. "It's hard, losing a parent. Nothing ever really feels the same after going through that."

"You mean -"

Caitlin nods resignedly. "Yeah, my dad passed away. Multiple sclerosis."

"I'm so sorry, Caitlin. I didn't know."

"It's okay. It happened years ago. That and - I know things are different now, and Barry's back, but if you ever do need someone to listen… what are friends for, right?"

"I appreciate that," Iris says warmly. "Okay, uh, I should really get onto finishing Barry's training programme -"

"Hey, no, it's okay, I'll do it," Caitlin says quickly.

"Are you sure?"

"Yeah, it's late. Go home to your fiance, Iris. I've got this."

Iris still looks unsure, so Caitlin gets up, reaches over her and starts clicking and typing.

"All right, well, before I go - you're coming to my bachelorette party, right?"

"You - you really want me to be there?" Caitlin says.

"Of course I do," Iris assures her. "You're coming. It'll be lowkey, though, don't worry. Just us and a couple of others."

"I'll be there." Caitlin takes the seat Iris has just vacated, and she watches as Iris gets her coat and purse. "And, uh, by the way," Caitlin adds, "for the record? You could totally pull off a strapless dress. And a train, if you're into that."

"You think so?"

"Yeah. But, I mean, you look good in anything, so -"

"You clearly have never seen some of my high school photos, then," Iris says laughingly. "But thanks. Here's to hoping I find the one."

"You will." And after a second, Caitlin adds, "I definitely did."

"All right, goodnight, Caitlin." Iris reaches out, touches Caitlin's shoulder and squeezes gently.

"Goodnight, Iris."

Wistfully, Caitlin watches Iris go, and it's only then that it occurs to her that this is the warmest her heart has felt in at least a year.

And when in a few days Killer Frost threatens to get out of control and Caitlin books a flight out of Central City, she shouldn't be surprised, really, at the dismayed look in Iris's eyes when Caitlin says she can't come to her party after all.

"Please? I know everyone's schedules are crazy, but this was the only day Felicity could do. And Linda said she couldn't make it because of a Rockets game in Star City that our boss is insisting she covers - and we work together every day, Cait, and we never get to do anything together, just us girls..."

Of course, of course Caitlin softens at that. It's impossible not to when Iris looks genuinely let down. "Well, when you put it like that..."

"Come on, are you really gonna say no to that face, girl?" Felicity says, adding as she pats Iris's cheek, "She does have a great face."

"Like you don't?" Iris says cheerfully, and she pulls Felicity into a one-armed hug before looking expectantly at Caitlin. "For me, Cait? Please?"

And truthfully, now, Caitlin couldn't say no if she tried. "Of course. I… wouldn't miss it."

Later, she regrets it, when Killer Frost comes to the fore at the restaurant. Caitlin remembers bits and pieces, but mostly it's just a blur, and she's not sure how she even makes it to Star Labs in one piece without Amunet catching up. And as she's stitching herself up Iris comes and helps her.

"You could have talked to me," Iris says. "I'm your friend, Caitlin."

"Work friend," Caitlin says after a moment's hesitation. "I mean, it's not like you and I have become besties over the last few years."

The words come out icier than intended, but it's no less true, and Iris sighs. "Yeah, I guess we haven't. But - come on. You saved my best friend's life."

"And then helped an evil version of him try to take yours," Caitlin adds bitterly. "You deserve better friends than me, Iris."

"Don't you think that's up to me to decide, though?"

And in that moment, it hits her - harder than any of Amunet's punches ever could, and Caitlin puts her head in her hands and tries to massage her throbbing temple with her fingers.

"You're right. For some reason you forgave me -"

"Because you're a good person," Iris insists.

"And I… I can see it now." Maybe the pain is getting to her head, or perhaps it's the confusion that comes after surfacing from a Killer Frost episode. But she couldn't stop even if she tried.

"See what?"

"Do you remember when you first came to Star Labs?"

Iris nods. "Yeah, when Barry was in a coma. I was… a mess."

"I knew he was - important to you. And vice versa. You had to be, if you were visiting him so often. But, um, when he woke up, he just - talked about you so much. And I knew he loved you, just… I think I understand, now, why he didn't say anything about how he felt about you. Because I get that feeling now - what it's like to come close to losing you. And I know I don't deserve that because we've never been best friends, but you… you've saved my life."

"And you've saved mine," Iris replies. "A few times now. Not to mention the lives of people I love."

"More than that, though. I get it now - I get why Barry loves you," Caitlin blurts out at last, and she kicks herself immediately as she watches Iris's expression change.

"What does that mean?" Iris says, but her tone isn't accusatory or disconcerted - it's gentle, the way she's always been with Caitlin.

And the words nothing and forget I said anything are on her tongue, but try as she might, she can't get them out. "You know what," Caitlin says eventually.

Iris looks like she's about to say something, but then the loud clack of heels sound and Caitlin looks up to see Felicity. When she sees Caitlin she looks apprehensive for a moment, but Iris immediately gets to her feet and her warm hand closes around Caitlin's wrist.

"It's okay," Iris says to Felicity. "It's Caitlin. Our Caitlin."

When the two of them walk towards the elevator together after what has been a very long night, Caitlin can't quite believe her ears when Iris says what she does.

"Weddings are all about new beginnings, right? So, what do you say? You wanna stand up for me?"

She could say a lot of things. She could say no. She could dance around it and end up saying she doesn't deserve it. But perhaps Caitlin is the most surprised of all when she says softly, "I do." And Iris smiles in that beautiful way of hers with just a little bit of sadness, tilting her head to one side, and Caitlin is sure Iris knows what she's thinking - she must do, because Caitlin has never been particularly subtle. Caitlin waits, waits for Iris to say something, but she doesn't, and then Caitlin says, "But I guess that's your line, right?"

Iris laughs, then reaches out, pulling her in for a hug. And Caitlin swears she could have stayed in Iris's arms all day, but all too soon she moves away as the elevator doors open and the two of them get in.

"Wow, I'm so excited," Caitlin says. "Do I get a bridesmaid's dress?"

"Of course," says Iris. "And, if you want, you can help me pick out mine, because I still can't decide. If that's okay with you, I mean."

"Provided no boys are allowed."

"Definitely not."

"And, uh, Iris? About… what I said, earlier..."

Once again it seems like Iris has read her mind because her expression changes from teasing to serious in a heartbeat.

"It's okay, Cait," Iris says quickly. "You don't have to explain yourself to me. Not ever."

"I know that." The elevator doors start to open as Caitlin adds, "But… I just wanted to say - Barry, he's a lucky guy."

"That I am," Barry says as Caitlin and Iris step out of the elevator together. "The luckiest guy in the multiverse, I'm pretty sure. Although in my defence, I did not know Ralph was going to take us to a strip club. And I didn't do anything he did, believe me."

Caitlin shakes her head. "That is a pretty low bar, my friend," she says. Then she turns to Iris. "You want to meet up tomorrow at Jitters? We could talk colours and, uh, flowers."

Iris smiles. "It's a date." She looks up at Barry. "You ready to go, babe?"

"Yeah, so I can sleep for a thousand years, I hope."

"I'll make you a greasy breakfast tomorrow morning and you will feel so much better," Iris says.

"Hey, hang on, I'm the only MD here," Caitlin says, pretending to look annoyed but not quite managing it, and the three of them laugh. "But yeah. Good idea. Take care, guys."

Iris reaches out, touches Caitlin's arm gently. "Goodnight, Cait."