Kidd gets a call from a distressed girl trapped in a basement.
The girl, who's name is Aaliyah, went to a Girls on Fire meeting at the beginning but didn't stick with it.
Aaliyah doesn't want to call the police and begs Kidd for help, even though Kidd has virtually no information to go on.
With the help of Severide, Boden, and Kylie, Kidd is able to discover the identity of the girl and rescue her and her brother.
Aaliyah then thanks Kidd, just as the firefighter is out the door to take the lieutenant's exam.
Brett reveals she and Grainger broke up, and Casey blames himself for getting in the way of their relationship.
Casey goes to see Grainger to try to smooth things over between him and Brett, but Grainger reveals things were never going to work out between them because Brett's in love with Casey.
Cruz struggles with swaddling, and Violet helps him.
Cruz then takes on Herrmann but loses to the father of five.
The internet at Boden's home goes out, and Donna teaches her classes from 51.
Gallo and Ritter are instrumental in helping her, and as a thank you, Boden agrees to give them a weekend off next month for their young firefighters' retreat.