Chanel Westermore grew up in the firehouse that her father worked at. Her and her older brother, Sean, spent most of their childhood with Chicago's finest and their children. One kid that Chanel and Sean bonded with was Kelly, a fire fighter's son. That was until their parent's split when Chanel was 15 and her mom relocated them to Missouri. Fast forward 15 years and Chanel is now a single mother of two who has escaped the grasp of her abusive ex husband. She's also followed in her father's footsteps and is going from being a firefighter in Missouri to recertifying in Chicago. She's even been placed on the same Truck in the same firehouse her father worked at Truck 81 of Firehouse 51. Little does she know, her first crush, first kiss, first best friend is right under her nose at Firehouse 51. But either way, coming back to Chicago is just what the doctor ordered for Chanel. She's landed her dream job and her kid's lives are better than ever. She feels safe being back with her father and not to mention that she's reconnected with her old middle school friend, Laura, who's husband is a Detective for the Chicago Police Department. Chanel finds comfort in knowing she's close with a family that has been through things just as traumatic and pulled through. Even though she has done pretty well with keeping her history of abuse a secret, somehow it comes back to haunt her. But how safe can Chanel possibly keep herself, her kids, family and friends safe and out of the cross fire of her past when she starts receiving threats from an anonymous person? Chanel thought her past was in the past, never to be resurfaced, but she couldn't have been any more wrong.

For the Casey family firefighting runs in the family! what will happen when Jenna Casey joins the one and only Firehouse 51

Hollie Halstead grew up an only child to an alcoholic, drug abusing mother, so on the day of her eighteenth birthday she ran away, got a job and joined the fire academy. 10 years later her mom is a thing of the past and she follows her own dream. To make Squad. Once she makes this dream a reality she is transferred to Firehouse 51 and joins Squad 3 only to have her life put into danger in the first shift.