Casey and Dawson apply for permanent adoption of Louie. Jeff Clarke gives Severide an interesting proposition. Otis convinces Herrmann to throw a bash celebrating the 100th anniversary of Molly's, but there are complications.
Louie's father throws a wrench into Casey and Dawson's family plans. Severide agrees to a bone marrow donation but a work accident throws everything into flux. Casey and Dawson try to find harmony at home. Meanwhile, Otis and Mouch decide to film a PSA encouraging people to join the Chicago Fire Department but hit a creative wall in the process.
Dawson tries to keep her emotions in check during an ambo run involving a pregnant teenager, while Casey is forced to make a split-second decision regarding two victims in need of assistance and deal with the repercussions.
When similar car accidents uncover the fact that someone may be targeting innocent people, a determined Dawson takes matters into her own hands to help push things along, meanwhile Casey tends to his Alderman's duties.