Doctors Manning and Rhodes suspect that two separate cases involving sick babies may be connected. A homeless patient's upbeat disposition enlightens Doctors Halstead and Charles, and Dr Choi and a Navy corpsman deal with the toll of gang violence.
After a balloon filled with cocaine bursts in the stomach of a student drug mule, the team frantically search for her three missing friends who have also been used to transport drugs and have been kidnapped on their return to Chicago.
Severide tries to prove his suspicions about the arsonist's identity, Casey gets accustomed to his new lifestyle, and Dawson goes on a date with a regular from the bar.
Voight calls the team to investigate a homicide involving the only witness in a rape and murder case against an extremely wealthy young man. Intelligence look into the suspect's family and finances as they try to determine if someone was paid to take out the victim. Antonio is offered a job with the state attorney.