The team is continuing to train Ralph as he gets used to his powers while Barry is trying to learn more about DeVoe. Felicity shows up as she is here to celebrate Iris' bachelorette's party.
Caitlin tries to back out of the party as she is booking a flight ticket to leave Central City. Iris and Felicity convince her to come anyway and she agrees to it.
The guys get together at Joe's house while the women head out for dinner. They go through a slideshow of Barry and Iris as kids which brings out all the feelings.
Ralph shows up and isn't impressed with the low-key bachelor party and suggests they head out to do it the real way. At a restaurant the girls are celebrating together while Caitlin gets nervous when one of Amunet's henchmen shows up.
He tries to attack but causes Caitlin to turn into Killer Frost who knocks him out. Elsewhere, the guys head to a strip club per Ralph's suggestion.
While they celebrate, the girls head back to Star Labs to figure out what's going on with Caitlin. Killer Frost reveals to the team that Caitlin was planning on leaving town tonight.
Barry is happy and drunk while Ralph plays around with his powers. But things get tricky when they see Cecile's daughter as one of the strippers.
Killer Frost heads to the club to see Amunet Black who is happy to see the ice queen back. The other girls arrive and try to find Caitlin.
Amunet shows Caitlin a metahuman she wants to sell on the black market. Iris sneaks in and sees what's going on.
Killer Frost needs to come back to Amunet to work as her personal bodyguard. But Frost isn't interested until Amunet start to use her powers as Iris interrupts the fight.
Amunet lets them walk away as she has a plan in mind. Back at Star Labs, Killer Frost explains how Caitlin got in Amunet's claws months ago.
Killer Frost takes off but Iris tells the others that they need to save the metahuman. The men ask Cecile's daughter why she was doing this.
Iris tries to get through to Caitlin in her Killer Frost mode. Back at the club Ralph and the gang gets in trouble with one of the club attendees.
Killer Frost finds Amunet outside Star Labs as she begins to fight her. She turns back into Caitlin before the cops show up to stop Amunet.
Amunet kills the cops as Caitlin gets away. Iris helps Caitlin take care of her wounds while she asks Iris what happened.
At the station, the guys are locked up as they got arrested for the fight. Barry begins to sober up while Joe talks about his fear of becoming a father again.
Harry arrives to bail them out. Back at Star Labs, Felicity analyzes the metahuman's tear that Amunet is taking advantage of.
They manage to track Amunet down but Caitlin doesn't feel comfortable going out there again, fearing Killer Frost will come out again. Elsewhere, Amunet is meeting with buyers to sell the metahuman.
Iris and Felicity try to strike but get stopped by the seller's guards. Amunet is amused to see Iris there but Caitlin shows up to save her friends.
She turns into Killer Frost and takes on Amunet. They come up with a plan to steal Amunet's magnets and Killer Frost attempts to kill her.
Iris talks her out of it as Killer Frost lets Amunet go. Amunet promises that this isn't over and leaves.
The guys arrive at Star Labs as Iris get them caught up on their night. They find Caitlin in her Killer Frost form as the whole team now knows her secret.
Cecile's daughter has a chat with Joe and admits that maybe Joe was right. Cecile arrives with food as they get caught up on their night.
Iris and Caitlin have another talk as they agree that they should try to hang out more together. Elsewhere, the metahuman is confronted by DeVoe.