Erin Noel Grennan

Two airplane stowaways are brought into the hospital after suffering major injuries from the travel, prompting Sharon Goodwin (S. Epatha Merkerson) to receive a visit from the Department of Homeland Security regarding the undocumented immigrants. Cornelius Rhodes (guest star DW Moffett), the wealthy father of Dr. Connor Rhodes (Colin Donnell), is honored after making a big donation to the hospital for a new psych ward, forcing dark family secrets to the surface. Dr. Natalie Manning's (Torrey De Vitto) big day arrives and Dr. Will Halstead's (Nick Gehlfuss) good intentions to help are misconstrued by her mother-in-law, Helen (guest star Annie Potts). Meanwhile, Dr. Sarah Reese (Rachel DiPillo) asks Dr. Charles (Oliver Platt) for advice on how to deliver heartbreaking news to a young boy while also warning his family about the possibility that their other son may also have the same life-threatening disease.

Members of the firehouse are frustrated with their inability to help Chief Boden (Eamonn Walker), whose job is on the line pending an internal investigation in the aftermath of a complicated call to a fire. Meanwhile, Lt. Severide (Taylor Kinney) struggles to accept his smaller role and adjusts to the presence of Capt. Patterson (guest star Brian White), his new commanding officer. Dawson (Monica Raymund) shakes things up on the work front and Casey (Jesse Spencer) attempts to find a crucial piece of evidence in his ongoing investigation against Nesbitt (guest star Eric Mabius). Elsewhere, Herrmann (David Eigenberg) struggles to keep the peace with Molly's newest neighbors.

The pressure on Firehouse 51 is at an all-time high as the internal affairs investigation into the handling of a recent fire picks up steam. Just when it appears that game-changing evidence comes to light that would serve to bail out Chief Boden (Eamonn Walker), new twists emerge that put his head right back on the chopping block. Brett (Kara Killmer) and Chili (Dora Madison) respond to a routine call and quickly find themselves in a life and death situation to help aid a stabbing victim who is bleeding out. Meanwhile, a stuck elevator summons the house to a high-rise hotel that tests everyone's mettle and candidate Jimmy Borrelli (guest star Steven R. McQueen) is conflicted when his older brother Danny (guest star Andy Ahrens) looks to get him transferred to a different house. Jesse Spencer, Taylor Kinney, Monica Raymund, David Eigenberg, Yuri Sardarov, Joe Minoso and Christian Stolte also star. Nick Gehlfuss, Oliver Platt, Brian Geraghty, Brian White, Rachel Nichols and Fredric Lehne also guest star.

Bull aims to raise reasonable doubt among the jurors in his friend Nathan's (Shawn Parsons) trial when the man is tried for his wife's murder and the prosecution's case is based on circumstantial evidence.

When a sports star is killed, Shaw and Riley suspect the shooter missed their intended target.