Archie shows the new interns around the hospital. Brinner comments on intern Tracy Martin's expensive heels. Tracy explains that all other shoes hurt her feet. Tony and Sam are introduced to the group before Frank sends them to the HR department for their IDs. Tracy turns the process into her own PR event, preening for the camera, donning make-up and creating havoc. Amid the chaos, new ER boss Dr. Banfield walks in and quickly brings the interns back to earth with a resounding thump.
Archie gives Dr. Banfield the lay of the land in the ER. Banfield is appalled at the lack of beds in the hospital. Sam asks if she can leave early to pick her son up after work and Banfield abruptly denies her request. Tony steps up and offers to pick up Sam's son after work. There's been a chemical explosion nearby and two patients, James and Decker, are wheeled in with injuries. Banfield annoys Archie when she announces she will supervise both trauma rooms.
Before entering James' room, Banfield takes a nervous breath. Her composure regained, she asks Archie why he uses an ultrasound. She criticizes him again before moving on to the next room. Banfield promptly tells Tracy not to get involved before criticizing Tony's treatment technique. As Brinner and Tony show their patient how to be calm to increase his well-being, Banfield tells them to act more professional. She reminds everyone she is responsible for every patient that comes into the ER and she has to be able to trust the doctors.
Dr. Crenshaw is on duty in the ER. He calls Lucien at home for surgery advice as Andrew Wade, Crenshaw's Intern, introduces himself. Neela tries to convince Dr. Anspar to reconsider Lucien's resignation. Gates tells interns Tracy, Ryan and Daria not to expect excitement on their first day. Archie directs Sam to park the explosion victims in the hallway; there are no beds, so they can't be admitted. Frank reminds Archie that one of their patients has been waiting five hours.
Sam examines a patient with a rash on his shoulder. The patient wants to know how long he will have to wait to see a doctor. Banfield interrupts and asks Sam for her diagnosis. Sam struggles and gets it wrong. As Sam deals with Banfield, an explosion victim, Felix, is wheeled in and refuses to be helped. In the trauma room, Tony cuts through a bag of Ricin as he is cutting off Felix's shirt. Tony barricades the interns in the room with him and calls Frank for help.
The fire department and hazmat team are ten minutes away when Banfield demands Trauma Two be sealed and the ER be evacuated. Sam shares her fears about the situation with Archie. Felix, who brought in the Ricin, is in pain from a broken leg. Tony can't do anything because they are trapped in the room without access to the right drugs to treat him.
Tony suspects Felix is bleeding internally in his leg and is forced to operate. He orders Ryan to get morphine but the intern can't find any. Tony decides to operate without any painkillers. As the man screams, another patient opens the curtain between the two beds. Outside, the fire department arrives and orders the staff to remove all the equipment they need. No one will be allowed back inside once the hazmat team arrives.
As the interns fret over the possible poisoning, Tony keeps working on Felix's leg. Tracy puts the man from the next bed back behind his curtain. The man, Jacob, has been admitted for bad asthma and is struggling to breathe. Felix tells to Tony that the Ricin was meant for government officials. He wanted revenge for his wife dying in the Pentagon bombing. Sam's patient with the rash is in a hurry and wants to leave. Sam gives him a prescription and lets him go, telling him to return the next day.
A mother and child are rushed into the ER. Banfield refuses them, declaring the hospital closed to trauma cases. Archie says he authorized them to come to County because they were only four blocks away and the child was in critical condition. Banfield allows them to be admitted. Meanwhile, in Exam Room Two, Tony deals with a ruptured artery in Felix's leg, and Jacob's lung problems. His only help are the incompetent interns. Suddenly Felix's heart stops. The interns panic. They attempt to shock-treat Felix and Daria asks why they are bothering to save a terrorist.
While trying to resuscitate Felix, Tony instructs Tracy on how to administer treatment to Jacob. Tracy injects Jacob's IV drip. Once both patients are stable, Tony wheels them out. They walk into a sealed quarantine corridor and are lead to a decontamination unit. Archie is busy attending to an injured child, Devon, when Banfield changes his treatment routine. Archie's temper explodes and he demands she stop micromanaging her staff. Neela takes Devon into surgery.
Outside, Tony and the interns have been decontaminated. Sam brings fresh clothes out to them. Daria announces they only have eight hours until they find out if they will die. Suddenly, Ryan collapses. Inside, Brinner asks Neela out for a coffee after the day is over. She ignores him. Amid all the chaos, Crenshaw has been seriously impressed by his intern Andrew's skills and knowledge. Outside, Banfield attends to Ryan and they try to figure out why he collapsed.
Paramedics deliver a drug overdose patient wearing a county ID bracelet. It is Sam's earlier discharge. While Archie attempts to revive him, Banfield notices track marks on his ankles that Sam missed. The overdose patient cannot be resuscitated, so Banfield announces the time of death. Frank is relieved to report to Banfield that Felix's Ricin was not strong enough to be poisonous. Neela watches as Crenshaw and Andrew operate on Devon. She returns to the ER, passing a staff sit-in outside Anspar's office in an attempt to get Lucien back.
Banfield tells Devon's mom she can see him as soon as he is out of surgery. When the woman breaks down, Banfield shows a softer side and comforts her. Watching from outside, Archie and Sam are confused by the polarities of Banfield's personality. Later, while Archie is helping get the front desk back in order, Banfield starts yelling at Archie to get a grip on his emotions.
Archie shouts back at Banfield, pointing out that her criticism and bullying will not earn respect. He storms off. Banfield finds him in the staff room where Archie unloads his anger again. She remains calm before telling him she knows about Greg. She then instructs Archie to never raise his voice to her again, and quietly withdraws. Neela nips Brinner's romantic advances in the bud by telling him they are work colleagues and nothing more.
Banfield tells Frank she thinks Archie is a slacker, but she still likes him. Outside in the decontamination tent, Ryan tells Tony and the interns the Ricin wasn't poisonous and that his fainting was psychosomatic. Sam announces to the interns that they are free to go home. Sam tells Tony she is glad he didn't die. Neela drops by Lucien's apartment. Lucien listens to her but he has decided it is time for him to move on. Elsewhere, Banfield sits alone in her home with a picture of her family.