A poisonous gas is released in a bank and the doctors try to contain the gas, that is threatening many lives including Dr. Hancock.

A cardiologist in NASA's Doctors in space program has a heart attack and Kate takes the doctors place in the program. Dr. Shutt has a patient who needs to tell his father, an Orthodox Rabbi, that he is gay.

Hancock accuses Watters and Austin of racism when they refuse to operate on a black patient. One of Shutt's patients commits suicide when the medicine needed isn't covered by insurance.

The hospital prepares for the Doctor of the Year party, and several old friends drop by. Watters goes into a virus-induced coma and gets some words of wisdom from Alan Birch. Camille Shutt returns for the party and Aaron discovers he still has feeling for her. Dr. Nyland returns to the hospital and reveals that he has really changed his life. Geiger also visits the hospital.

Kate discovers that a patient is using Viagra to cheat on his wife; Jack gives a blood transfusion even though it's against the patient's Jehovah's Witness religion; a musician fears his creativity may be stifled by the medicine Aaron prescribes for his bipolar disorder; Joe's son drives the staff crazy as he roams the hospital behaving exactly like his father.

Gordan teaches Kate how to fly. Hancock accuses a police officer of shooting a homeless African-American.

A celebrity dies and news crews invade the hospital to cover the story.

Billy's mother shows up at the hospital and announces she is about to give birth. The star of the road company version on ""Jesus Christ Superstar"" comes to the hospital when the star is ill. Yeats former teacher comes to the hospital with chest pains.

Wilkes must face the parents of a child brought into the ER when it becomes clear that Raymond was responsible for the child's injury. NASA starts interview Kate's colleagues. One of Aaron's patients is attracted to him.

A member of Jack's basketball team sustains a near-fatal injury during a game; Bobby disagrees about the need for his patient to have heart surgery.

Aaron struggles with the loss of a patient; Billy is attracted to Emily's babysitter; a couple asks Bobby and Dennis for help in creating a baby with a genius I.Q.; Joe tries to decide who should go into the hospital's fallout shelter in an emergency.

Kate discovers that she has developed an ovarian cyst which could destroy her plans with NASA. After Kate hears this news she agrees to go to a retreat... that Yeats is leading.

During surgery to resolve an HIV-positive woman's post-partum complications, Diane accidentally cuts herself and is exposed to the virus; problems arise between Jack and Lisa when he discovers that she's been seeing Robert; a homeless man takes shelter in the hospital's main entrance; an unidentified man is hit by a train after trying to save a child; Jack takes up golf in the hospital.

McNeil performs a hand transplant on the patient, and uses the patient's dead mother's hand. Kate is accepted by NASA. An old childhood friends visits Watters and asks for one of his kidneys.

Jack returns after his brother's death; fearing the impact of HMOs on his practice, Joe begins to sell doorway products; Billy's friend comes to the hospital for a heart transplant, and ends up getting an experimental procedure after the hospital receives the wrong organ.

Billy ponders euthanasia when Gordy is diagnosed with rheumatoid arthritis; Lisa tries to help a woman with metastatic breast cancer get into an experimental group even though the woman doesn't fit the study parameters; Aaron's patient confesses to murder.

Kate confronts a world renowned surgeon who's harassed her in the past; Diane's patient has a flesh-eating bacterial infection.

Diane tries to help grieving parents when their three year old child dies; Aaron is institutionalized after an experiment backfires.

A mother gives birth to twins, one black and one white. Kate is threatened with a lawsuit after making a rude comment.

Dr. Hancock's patient, who was using fertility drugs, gives birth to 8 babies.

Kate meets up with an old boyfriend, who turns out to be an ex-husband. Lisa tried to prolong the like of a pregnant woman with brain cancer. Cacaci forces Aaron to investigate his charge that Phillip had an affair with a patient.

The E.R. is flooded with teenagers poisoned by an unknown rave drug; Kate and Sara are hit by a drunk driver; Phillip's fate is decided.

Aaron consults Dr. Gina Simon, a pediatric neurosurgeon after being presented with a 9-week old baby suffering from seizures. Jeffrey Geiger returns to the hospital and promptly fires half the staff, whom then sue to get their jobs back.