Third-year med student Lucy Knight reports to the ER for the first day of her rotation. Greene takes a paternal interest in her, helping her get acquainted, but she gets off to a bad start with the irritable Carter. The rest of the day finds her informing a wife of her husband's terminal condition, comforting a pregnant woman, getting locked on the roof and trying to figure out Weaver's "Tour on Tape."

Benton performs dangerous surgery on a bomb-carrying man who was shot at a factory. Dr. Ross receives some good news that Dr. Weaver doesn't embrace, but she has no recourse. Rachel encourages Dr. Greene to help a horse that is in pain. Jeanie Boulet returns from her vacation.

It's Halloween in the ER, and the medical students throw a party; as a result, Carter decides that Lucy isn't mature enough to take responsibilities. A candidate for the ER Chief position arrives from New York and drives home disappointment for Kerry. Mark screws up when he doesn't recognize a homeless schizophrenic woman is pregnant before treating her. Benton treats Corday to a fun Halloween.

The board decides to extend the search for a new ER Chief, leaving Kerry waiting for a decision. Benton visits a doctor who is deaf and he realizes that there is nothing "wrong" with his son. Mark saves the life of a gay prostitute and then tries to get the kid to avoid reckless behavior. Carter loses his Resident Advisor job because of Lucy, then blames her for not going along with his plan to defraud an insurance company, but she inadvertently leads him to shave off a nasty-looking beard he'd been growing. Corday saves two lives and impresses Benton enough that he decides to request she be his intern instead of Dale's. Carol tries to help an elderly Jewish guy find a place to live.

Carter and Weaver become unlikely roommates. Lucy is having problems with Carter, and Greene picks up on their squabbling. Corday works long shifts which leads to her exhaustion and a critical medical error, causing a rift with Dr. Anspaugh and problems for Benton. Greene has unpleasant flashbacks when he's hazed by the well-meaning paramedics. Jeanie worries when she and Doug treat a young boy whose childlike mother clearly depends on his 6-year sister to make all decisions. Kerry rediscovers her joy of practicing medicine and decides not to pursue the open ER Chief job, which goes instead to a Dr. Amanda Lee.

A man arrives at the ER with his gravely-injured daughter then runs out, presenting a critical situation because he's the only match for her blood type. While Carter and Lucy alternately bicker and work well together as they try to track down the father, blood-supply snafus spur Benton to perform an unprecedented operation on the girl.

Corday faces M&M where the board was discussing the mistake that Corday made after she gave the wrong dosage to a patient. She decides to take the offensive and let the board know how wrong it is for her or any other doctor to work 36 hours. The board decides to do nothing about it, and she later decides to amicably end her relationship with Benton. At the hospital arrives Ruth Johnson who was born 100 years ago in that same hospital and shares some experiences with Carter. Carol is horrified by the truth behind a young boy's fatal shooting.

Dr. Greene tries to help get Amanda Lee the proper credit she deserves on a paper she wrote. However, he starts to become suspicious of her credentials. An old friend of Dr. Greene recommends him for a NASA mission. Benton's son is having difficulties in day care. Doug and Carol help the exhausted mother named Joi of a little boy named Ricky who has a terminal illness. Carter is jealous when Lucy goes on a date with Dale.

Romano observes the ER, and rubs the staff the wrong way. Lucy finds out that an elderly patient's bedsore is really much more. Carter breaks up with his girlfriend. The power goes out at County General, and the doctors must keep critical patients alive. Corday investigates the rape of a comatose patient.