Several long term characters exit the series including Corday who quits after performing an illegal operation, Chen leaves to care for her ailing father and Carter also departs the ER to return to Africa with Kem.
Elsewhere Lewis is promoted to ER Chief, Abby and Neela begin their internships along with newcomer Ray Barnett, Carter and Lewis compete for tenure, Weaver finally meets her biological mother, Kovač and Sam's relationship deteriorates and Gallant makes an unexpected return from Iraq.
After doing a brief shift as a nurse to help with Pratt, Chen and Elgin's absence, Abby starts her career as a doctor by dealing with a drug-smuggling patient, ultimately convincing the girl to give up the drugs on her own rather than undergo a far more invasive cavity search.
Two small children are rushed to the ER after falling from a third story window, allegedly escaping their mother's violent, abusive ex-husband; however, additional facts reveal a different cause.
Corday is disciplined over her illegal surgery, and instead of taking a non-tenure track position, she decides to call it quits and return to England.
Pratt heads to Chen's house and finds she is about to euthanize her father, who has begged her to do so in his lucid moments and then take his body back to China.