Trama

Barry's desire to keep the team safe is tested when Frost recklessly courts danger while trying to stop the Black Flame; Iris tries to help a teen girl reunite with her mother but unintentionally does more harm than good.

Frost and Carla come up with a plan to capture the black flame, but both Barry and Caitlin are worried that it's too dangerous. Meanwhile in Coast City, Iris and Sue help Tinya find their mother, but Iris' temporal sickness puts her in danger.—Gislef

In Coast City, Iris asks Deon what's happening to her. He tells her that the time anomalies he's been tracking lead to her, and there's something about her that's causing time to fracture around her. Iris realizes that her "sickness" is coming for her, and she sends out a signal that brings Barry to her side. She tells him what has been happening to her, and Deon tells Iris that she has to stay put while he finds a way to stabilize her. He tells her that she should limit her movements to Coast City, and Barry worries about what happens if Iris has another episode. Deon says that he'll have to do something radical to patch Iris up. Iris agrees, and Deon concentrates on her and she winces on pain.

Deon teleports out and Barry says that he's going to grab some things from home and come up. Iris tells him that he has to deal with the black fire, and Sue will be with her. Barry reluctantly agrees and speeds back to Central City.

The next day in Central City, Frost is in her apartment painting. She notices that she's swearing, and turns the temperature down. Black fire spurts out from her painting and brushes past Frost, burning her arm.

At the CCCM, Barry meets with the rest of the team and tells them about Iris' situation. Cecile and Joe confirm that none of the black fire victims have anything in trouble, and the black fire attacking Chester doesn't make sense since his father died when he was a kid. Allegra has assigned Vanya and Aariz to check the victims' background, and Joe and Cecile are going to go through the background files on the victims that Kristen got for them.

After they leave, the team gets an alert from the medbay at STAR Labs. Barry speeds there, and Frost tells him that the black fire attacked her and burned her arm. He bandages her wound, and figures the fire attacked her for a reason. Barry asks Frost for permission to search her apartment, and Frost agrees. Once Barry leaves, Frost goes to meet with her daughter and tells her about the black fire murders. She figures the fire is coming after her, and wants Carla to use her as bait to catch the black fire killer.

Carla and Frost go to STAR Labs and tell the others that they plan. She figures cold fusion is involved, and the black fire is hunting Frost for fuel. Once it comes for Frost, they can track it. Barry objects, pointing out they don't have any way to trap the fire. Carla has come up with a way, and Chester figures they amplify Frost's signature and the Fusion Sphere from the ASF can handle it, if he and Carla can recalibrate. Frost refuses to sit around and do nothing when the fire is coming after her. Barry refuses to put Frost in harm's way and leaves.

Carla insists that it could work and goes to work, and Frost goes after Barry and points out that Iris isn't going to stay put. She says that Iris is helping people like the rest of the team does, and she wants do to the same. Frost asks Barry why he won't give her the same chance he's giving Iris, and Barry reluctantly gives in.

Chester and Carla finish recalibrating the sphere. The others are there, and Carla and Chester activate the sphere to draw the fire there and then contain it in the sphere. Barry figures it won't take long to lure the fire in, and Carla tells Frost that Frost is very brave. The fire arrives through the ceiling but stops. Frost yells at it to come get her, and fires an ice blast at it. It knocks her unconscious and leaves, and Barry goes to Frost. They take Frost to the medbay, and Caitlin checks on Frost. Caitlin says that Allegra told her what Frost was doing, Barry tells Frost what happened after she was knocked out, and he says that he search the entire city and didn't find the fire. Frost and Carla insist that they have to try it again, but Caitlin refuses to let Frost endanger herself and tells Barry to leave so her family can leave.

In Coast City, Iris, Sue, and Tinya go to the adoption agency. The receptionist refuses to give them the background on Tinya's adoption, and says that she checked the files and there's a no-contact order in place. Tinya insists that she has a right to know the truth and phases through a stapler by mistake. The receptionist says that the board would have to drop the order, and Sue calls her uncle to have him use his influence. He talks to the receptionist and has her give them the info on a flash drive.

The receptionist goes to take a break, and when she goes to get some coffee, she comes back to discover all the furniture in the room is gone. Meanwhile, Sue goes to get her car and Tinya wonders to Iris if he mother wants to meet her. Iris sympathizes because of her own relationship with her mother, and someone made her realize that reconnecting with her mother was a gift. She tells Tinya how she did it, and assures the girl that Tinya won't have to do it alone. Tinya takes the flash drive and goes.

Caitlin tells Frost that she has to stop putting herself at risk. Frost insists that she's trying to help people, and Caitlin asks Carla how she could go along with Frost's plan. She says that they made a decision to protect people, and Caitlin tells her mother that she sees Frost as a science project, not a daughter. Caitlin tells Frost to value her own life, and Frost asks Carla if she thinks the sphere will work. Carla says that it will, and Frost walks off despite Caitlin's objection. Caitlin tells Carla that she'll have no daughters if something happens to Frost, and walks out.

That night, Joe finds Barry in the lounge and tells her that Carla told him about Barry's objections to the plan. Barry agrees that they need to do everything they can to stop the fire, but insists that Carla's plan is to dangerous. Joe figures that Barry is concerned about something else, and says that as team leader coming up with a plan that keeps everyone safe is his job. Joe wonders if he's talking about Frost or Iris, and points out that Barry treated Iris differently than Frost. He says that the hardest part of being a leader is trusting the people, and then being there if they need him.

Carla goes to see Frost and tells her that she is Frost's mother, and it's time she start acting like it. She figures that Caitlin is right and Frost has to stop being reckless, and Frost can't help anyone if she's dead. Carla says that Thomas would do anything he could to protect his family, but took it too far. She assures Frost that she's a vital part of Team Flash and the Snow family, and she's Carla's daughter. Carla says that there's a time for protecting oneself, and now's the time to protect herself.

Frost still wants to lure the fire to her, and Carla suggests they need a secondary cryo-signature to attract it. Carla says that she has the potential for ice powers, and she can combine it with Frost. Caitlin comes in and admits that Carla is right, and they can trap the fire if they work together. The alarms go off as Chester and Allegra detect the fire downtown.

Carla tells Barry her abilities, and Barry says they'll help her with her powers if she decides to explore them. As they set up the sphere, Barry tells Frost that he trust all of them, but will get them out if he has to. Frost assures Carla that what she's doing will save lives, and afterward they can get dinner together.

Barry activates the sphere and Frost shows Frost how to activate her signature. Their bio-signatures are in sync, and the fire heads for them. It enters the speed lab and is sucked into the sphere, but the sphere integrity is lost and the fire tries to break Free. Carla insists they can do it, but Caitlin confirms her mother is going into cardiac arrest. Carla insists she can do it, and Frost pulls Carla free as the fire escapes.

Barry goes to Frost and Carla. Frost tells Carla that it's okay they didn't get the fire and it's okay, and hugs her "mother".

When Joe and Cecile arrive, Frost says that they let the fire ago. Barry and Caitlin both say she did the right thing, and Joe agrees. He says that they'll stop it, and Carla will make a great meta. Cecile and Joe say that they found nothing, and Barry figures if they can create a strong enough signal, they can lure the fire back to the sphere without risking anyone.

Frost and Caitlin take Carla to their mother, and Caitlin apologizes for yelling them. They say that they both needed to hear it, and Caitlin gets a call from Marcus. Frost tells her to tell Marcus everything, and Caitlin agrees but not that night. Once Caitlin leaves, Frost and Carla agree on brunch. Carla apologizes for not telling Frost about her condition, but she was worried about what it would mean. Frost suggests if they had talked more, Carla would feel more comfortable. Carla says that she missed much of Frost's life, and there's a lot about her she wants to know... and Frost is her daughter, and she loves her more than Frost could know. Frost is surprised, and Carla hugs her.

Tinya, Iris, and Sue go to Tinya's mother Renee's apartment. When Renee opens the door, Tinya tells her that she's her daughter. They go in and mother and daughter talk, and Tinya asks Renee why she didn't want her. Renee says that she always wanted her, but she 16 and confused. Her parents convinced her to give Tinya away, and Renee says that they were wrong and she never regretted anything. All she could do to get through her life was hope Tinya was living a better life without her. Tinya says that she isn't, and she needed her mother.

Iris winces in pain, and then her eyes glow green with temporal energy. Renee disappears in a flash of temporal energy, and Tinya asks Iris what she did to Renee.

The next morning, Caitlin is getting coffee when the fire comes in. It tells Caitlin that there's no normal life for them, and the world is different now. Caitlin realizes that Ronnie told her the same thing, and calls his name.