Flames of the Heart (book 1; Kelly Severide love story)

Maxine "Max" Halstead, the youngest Halstead sibling starts working at Firehouse 51. As Squad's new candidate, get's accepted fast by everyone and get's along great with everyone as well. A few pranks here and there, laughs, everything that you get from a firehouse.
As Jay and Will, made clear (or asked) Squad and the Firefighter's to keep an eye on her.