The staff of Gaffney Chicago Medical Center's new ER are given a baptism of fire when the department's opening is interrupted by a train crash.
Dr Choi treats a teenage mother who abandoned her newborn baby in an alley. The nurses surprise Dr Manning with a baby shower.
Dr Rhodes takes on a tricky case with a familiar patient, and Dr Halstead must decide whether to gamble on a young musician's hearing by performing surgery.
A mass shooting at a cinema inundates the hospital with gunshot victims, including the shooter. Dr Rhodes faces a crisis of conscience.
Rhodes and Zanetti race to save a member of Firehouse 51, April's brother struggles during his first day at the hospital, and a woman saved from a burning building leads to a bigger mystery.
Dr Rhodes tends to two injured aeroplane stowaways, but their treatment becomes complicated when the Department of Homeland Security arrives.
Oliver Platt
Dr. Daniel Charles
S. Epatha Merkerson
Sharon Goodwin
Nick Gehlfuss
Dr. Will Halstead
Marlyne Barrett
Maggie Lockwood
Yaya DaCosta
Nurse April Sexton