Halstead goes undercover to investigate the death of a teen who ran away from a treatment centre for troubled girls.
Severide agrees to a bone marrow donation; Casey and Dawson attempt to find harmony at home; Otis and Mouch plan to create a PSA to encourage people to join the Chicago Fire Department.
Dawson and Casey face legal issues as they try to retain legal guardianship of Louie; Severide continues to look for a bone marrow procedure to help Anna; Brett opens up to Dawson.
Kidd is forced to deal with the unpredictable actions of her ex, while Chief Boden struggles with Jimmy, and Dawson faces a decision on her foster care with Louie.
Dawson tries desperately to save a trapped boy from an apartment fire. Severide decides the firehouse's fire masks need upgrading.