"Chopper"

Boden is with Donna as she gets an ultrasound and they agree to wait to find out the sex of their baby. The doctor then tells them that Donna has a condition called placenta previa, which outs her and the baby at risk in the third trimester.

Brittany wants Severide to call in sick to work and spend the day with her, but he says he can’t. Then she asks him to promise that he will be safe.

Casey sees Cruz and Brett whispering about Zumba and assumes they have a thing.

The squad is called to the scene of a downed helicopter that has exploded on the roof of an apartment building.

On the way to the scene Brett asks Mills about keeping a secret with someone in the firehouse for personal reasons. He tells her that in his experience in house relationships are better kept out in the open.

Severide ignores the 37 text messages from Brittany and continues with his job. On the roof Severide tends to the pilot and two passengers still stuck in the helicopter that is dangerously balancing on the roof. Mills and Brett go around helping all the victims on the ground. Boden tells Otis and Herrmann to find the missing rotor, they then find it in a yard with a women pinned under it, so Otis and Herrmann try to help her.

Then Brittany shows up to the helicopter scene worried about Severide because she heard his voice on the radio. Boden tells her she can’t be here and moves her behind the tapeline and tells her stop worrying and let Severide do his job.

Mouch and Cruz come out of the building, but Dawson still didn’t come out. Casey is worried so he goes to go back in but then there’s an explosion from inside. After the explosion he went to go back in but then Dawson comes out, he yells at her for giving away her mask and then tells her to go get checked by the paramedics.

Herrmann and Otis realize that the only way they can help the lady under the rotor is if they take the rotor apart. Otis runs to get tools from the truck, while he’s gone Herrmann tries to make conversation with the lady, he then makes her laugh, which hurts her then she says don’t make me laugh. Then Otis gets back with tools and frees her, she hugs Herrmann. Otis notices something on the rotor; it’s a remote controlled drone.

Dawson then sees a trail of blood leading to a shed. Inside she finds a man with a head wound lying on the floor clutching a remote control. He apologizes for screwing up, and tells her his name is Alan and she has him holding a cloth on his head. Mills then goes to help Dawson leaving Brett alone with a victim that is trapped by the helicopters tailpiece. After they broke into the van to get him out Brett notices a bag full of passports. After Mills leaves the man in the van wakes up and starts freaking out. Brett yells at him to let her do her job, and he pulls a gun on her and tells her he is not going to the hospital.

While Dawson and Mills are helping the man named Alan he says that his brother Jack was with him on the roof flying their dads drone when the chopper went down.

Dawson told Boden over the radio that there is a victim down on the roof beside the apartment. Casey and Cruz go to search for Jack and end up finding him near a live wire and a transformer. Casey jumps over the fence while Cruz goes to see about cutting the power. Cruz comes back and tells Casey there’s no way to cut the power. Jacks foot is stuck in barbed wire. Casey cuts the wire from around Jack’s food and drags him away just as the live wire touches Jack’s blood on the ground. The transformer then explodes but Casey and Jack are both okay.

Severide frees the pilot of the chopper but the two passengers are still pinned inside. As the chopper balances on the roof Severide works to free them, pieces of the roof keep falling down to the ground making the Chopper fall a little more each time, Boden radios Severide and tells him he has to hurry. Severide gets the passengers out but he is still inside. As the chopper falls a little more Severide jumps out and is okay.

Dawson helps Mills load Alan onto the ambulance and the two share a laugh, saying it feels just like old times. Brett then returns to the ambulance and tells Mills her patient refused treatment. Later Brett realizes that Mills’ had a relationship with Dawson; he tells her he will explain the whole story over beer some other time.

Casey wants to get a hotel room for him and Dawson to celebrate their big saves. She realizes he doesn’t want to go home because he didn’t tell Severide that he has to leave.

Cruz asks Brett if she is okay and then gives her a “Free Class” pass for Zumba. Casey sees the moment and confronts Brett about what he thinks is a romance happening. Brett says no its not like that then asks Casey if he can keep a secret and tells him how Cruz is a Zumba instructor. But of course Casey can’t keep a secret and tells Dawson who tells someone else and so on.

Herrmann tells Boden to stay positive about Donna’s condition. He told Boden to just put his arm around Donna and say everything will be alright he knows from experience. Boden asks what if it isn’t alright?

As Brett drives home from the station an unknown car is following her. She is scared so she takes all kinds of different turns trying to lose him, she turns into a dead end ally as he passes she thinks that she lost him but then he backs up and pulls in behind her. She is afraid that he wants to hurt her but he just wanted to say thank you for saving him.

Boden meets Donna at the doctor’s appointment and she tells him that they are going to be having a boy, Boden starts crying of happiness.

Severide and Brittany fight about her showing up at the scene. Dawson and Casey think this may be the end of their relationship but then overhear them making up....

While Cruz is preparing for his class one of his students come in and tell him he has a full room today. He enters the room to find practically the whole firehouse in his class. He wants to leave but they convince him to stay and lead the class because they paid a lot for it and also they showed up to support him.

Brittany and Severide are talking and he tells her that her tattoo of her sisters name looks new, she tells him she adds onto it every now and then so she remembers the accident. She apologizes for showing up at the scene and tells him she was afraid she was going to lose him. She told him he is the only one that understands how it feels to lose someone.