Boden thinks he's being set up by his neighbor; Severide's father pays him an unexpected visit; romance is in the air at the Chicago Fire Department gala.
Patterson questions Boden's ability to lead the firehouse as the trial approaches; Brett and Chili find an unconscious man in a garden; Otis tries to fill his social calendar.
Members of Firehouse 51 are unhappy when Patterson fills in for Boden while he tries to clear his name; Severide may have found Serena; Chili and Jimmy attract more attention than they expected.
A member of Firehouse 51 is treated for life-threatening injuries; Cruz searches for Freddie; Mouch has a surprise for Trudy; Chili's behavior worries Brett and Jimmy.
The city prepares for a tornado; Brett is forced to go to Boden about Chili's erratic behavior; Otis asks Dawson for help with his women trouble; the Department of Homeland Security asks Severide for assistance with a suspicious home.
A mother becomes Stabler and Benson's prime suspect in the poisoning of her child; Novak enlists Clark's assistance in obtaining evidence to remove a judge from the bench after his bias in two child abuse cases leads to a wrongful arrest.
Benson and Stabler have a suspect (Alfred Molina) but not enough evidence when a serial rapist preys on illegal immigrant women, and Tracy Kibre (Bebe Neuwirth) is brought in to work on the case.
A car accident involving two foster children leads detectives Beck and Stabler to the foster parents and questionable medical practices involving a controversial "rebirthing" therapy.
When a mob lawyer (Cary Elwes) and his wife are attacked, their young son is the only witness; when he comes out of surgery, the man vividly remembers his daughter at the crime scene.