Abby awakes after the explosion and helps other victims despite her injuries, while Morris is left picking up the pieces after Pratt's death. Neela struggles to keep up with the rush of injuries.
Staff in the ER come to terms with the loss of their colleague. Gates and the new interns treat a bio terrorist, who has a lethal secret that endangers them all.
Abby's first day in her new job proves bittersweet. Neela is hurt when she finds out Abby's big news from someone else, and Abby and the new ER Chief argue over how to treat a gunshot victim.
Dubenko returns to work, due in no small part to Brenner's organised protests, but Brenner asks a favour of him in return. Banfield is forced to defend herself from a man trying to steal her wallet.
Gates feels neglected because Sam is distracted while studying for her pharmacology exam, while a school fight results in a stabbing and a nose that won't stop bleeding
Chaz, now a med student, begins his er rotation. Morris takes him under his wing and shows him some risky procedures, endangering a patient and raising Banfield's ire. And Gates oversteps his bounds.
Banfield finds herself trying to rescue a young girl from drowning in a lake, triggering memories of the time her son was in mortal danger. Gates tries to pull strings to help his homeless war hero.
Gates goes out looking for a homeless war hero, Neela's med student gets the department into a lawsuit, and Brenner gets into a fight with a patient
Neela must testify in court and defend her actions regarding a patient who died. Sarah and Alex defy Sam and sneak off to a party.
A package for Morris from his deceased father is delivered to the ER, and Sam is anxious about Alex being removed from the ventilator
Tensions continue between Gates and Sam, coming to a head when Tony discovers he is the last to know about Alex's impending release from hospital
Neela has recurring dreams about trying to save a girl with sickle cell anaemia, seeing an old colleague and having conversations with Ray
Morris treats a teenage girl who is acting in an agitated manner after being injured while riding her bicycle. Sam is furious with Gates over Daria. Meanwhile, Neela is flustered when Brenner returns.
Gates and Morris tend to an elderly man who has been assaulted on the street. Brenner and Dubenko clash while treating a mother who looks to be in the late stages of cancer.
A young girl needs someone to look after her when her mother is incapacitated, but Brenner can't find anyone to do it. Morris is stymied when an elderly man needs an MRI but insurance won't cover it.
Determined to have a baby, Cate comes up with a plan in which her niece would donate some of her eggs, but she has difficulty in getting Russell's agreement. And Dr Carter makes a surprise return.
Carter is confused by the new procedures and technology introduced since he last worked at the ER, but his experience and intuition see him through. And Sam is shocked by her mother entering the ER.
A crew shooting footage for a documentary interview members of the ER staff. Detective Claudia Diaz is brought in, critically injured. Meanwhile, Carter's condition worsens.
George Clooney, Noah Wyle, Julianna Margulies and Eriq La Salle reprise their roles in this episode, with guest star Susan Sarandon as the grieving grandmother of an organ donor
Neela proves her worth as attending material when she clashes with Dubenko on how to proceed with two different surgical cases, while Brenner gains a deep insight into his painful childhood
The ER staff help out at a camp for kids who have had heart surgery. Working with the camp counsellor, Morris and Brenner make an impact on some of the kids.
The medical drama finishes its 15-year run with an extended episode. Old friends come to show their support when a new medical facility for the underprivileged is opened.