Tan finds himself on a one-man mission to save his new love interest and her journalist co-workers when mercenaries take over a black-tie correspondents' dinner. After the group escapes, it's up to SWAT to track down the well-trained gunmen before anyone else is killed. Meanwhile, Hondo and Nichelle return home to find their house trashed, placing them at odds when it's revealed that Nichelle has a secret. And when Hicks, Mumford and Buck take a trip down memory lane, it threatens to end their decades-long friendships.
McCall races to help Dante and Big Ben after they are ambushed by a group of suspicious attackers and a major family secret is revealed. Meanwhile, at a party celebrating 50 years of hip-hop, Aunt Vi tries to maintain her status as the reigning queen of the annual cobbler baking contest and Dee suspects a mutual friend may have stolen prize money.
Shaun, Jared and Charlie's young patient need his parents to agree on an important medical decision that could greatly improve his health; however, his parents are unable to agree on the correct path which spurs the team to try and intervene on behalf of their patient.
Late-night passengers get stuck in a tunnel when their train breaks down. Patiently, they wait for the replacement service until a nurse gets her purse stolen and tempers start to fray.
Walker, Trey and Cassie prepare for what Captain James has in store for them at HQ. Meanwhile, Stella and August start to put some pieces together. Lastly, Walker makes plans for his future and Liam questions his brother's motives.
Ripley struggles to keep Sully's diagnosis a secret when the latter's pregnant girlfriend comes to Med for help. Loren works to earn a spot in Med's trauma fellowship. Charles and a medical student treat a bipolar artist.
Severide goes for an unexpected ride on Truck 81. Ritter's worlds collide when his secret cop boyfriend helps 51 track down Severide and the missing rig.
George Sr. is worried that Mary wants another baby and gets a vasectomy behind her back. Meanwhile, Drs. Linkletter and Sturgis go to Sheldon for science tutoring.
An unexpectedly complex case brings back painful memories for Simone. Jules and Blue make a high-stakes bet on who can finish their procedure log first. Richard suspects Winston is avoiding him.
The crew responds to a call at a local park, only to have their assumptions challenged by the Tulalip Tribe when they arrive. Meanwhile, Maya confronts her past, and Carina goes on the offense.
