Kate returns to Chicago to face possible arrest and her ex-husband, as well as suspension at work. Aaron ponders Philip's bitterness over Aaron's apparent support of Tommy Wilmette. Dennis struggles to regain his health. Dr. Nyland returns to find a new doctor in charge of the trauma service. Kronk and Grad continue to quarrel as he prepares to leave Africa.

Kate cares for her dying father and gets some words of wisdom from Tommy when he brings Sara for a visit; Philip recruits Dr. Jack McNeil to head up orthopedics; Diane returns, only to find that Billy has remained in Africa and that her lab has turned into a storage room; Keith places himself in legal jeopardy when he decides to help an injured drug courier evade arrest; Aaron persuades Tommy to give the hospital six months to turn itself around with Philip at the helm.

Aaron and Jack join forces in operating on a man who sustained multiple fractures in a parachute jumping accident; Diane rejoins the staff as a teaching attending in internal medicine, and quickly draws a demanding and manipulative patient who's making the staff miserable; Kate's grief over her father's death is compounded when she's carjacked on her way home from his funeral and his ashes are not recovered with the car; Diane unsuccessfully seeks some moral support from Dennis and Philip; after Tommy tells her some hard truths about creating her own misery, Kate decides to take responsibility for the choices she's made, and starts by telling Peggy Harrod the truth about her daughter's death; Jack takes one on the chin when he gives the parachutist's would-be bride some bad news; Kate returns home to find the carjacker has returned her father's ashes while burglarizing her home; Philip has it out with Aaron and reaffirms his intention to keep Tommy from closing the hospital.

Dennis and Jack clash over the best mode of treating the arthritic knee of a world class cyclist; Aaron makes a new friend when he takes on a new research assistant; Kate and Danny have their suspensions reviewed by the board; Phillip plunges back into patient care by performing an experimental procedure on a woman who exhibits unusual complications from a liver tumor; Caroline discovers that orthopedics are not for her; Dennis faces an emotional struggle in the aftermath of his shooting.

Kate returns to duty and finds that her reinstatement comes with a cut in title, salary, staff, and office; Jack replaces the hip of an older man who has opinions on everything, including how Jack should live his life; Aaron has mixed emotions when Grace comes up with a much-needed improvement for a surgical shunt he's been developing; Kate is humbled when a young couple whose daughter needs a heart transplant chooses another doctor after they discover her change in status; Tommy thinks it would be a good idea for the hospital to advertise, and hires a publicist who manages to get under everyone's skin as she creates a commercial that ends up looking strangely familiar.

Austin sprays a subpoena server with mace, inspiring his fellow servers to wage war on the hospital. Hancock tries to counsel a woman in her late forties whose health is severely threatened by her pregnancy but who refuses to let the baby be delivered early. Kronk finally returns to Chicago, dressed in Masai garb, and tries to reconnect with Diane.

Aaron faces a huge moral dilemma when he's asked to operate on a death-row inmate scheduled to be executed in two weeks. McNeil treats a feisty old lady whose daughter is an old flame os his. Dr. Watters entertains an amnesiac, believing that he's a distinguished visiting doctor.

Austin's cystic-fibrosis patient is just one of four patients needing transplants who have to wait in fear and hope when a potential donor appears but is prematurely pronounces dead and entered into the donor system by the inexperienced Eggert.

Kronk puts himself and Grad into a difficult position when he treats an old hockey pal who turns up after just being released from jail with a bullet in him. Wilkes and his wife face some basic decisions about their lives when they must decide what sort of neighborhood to move to.

Austin and Underhill both have to face the consequences when they tell the truth. McNeil contemplates surgery to prolong a jockey's career. Kronk lies to a teenage smoker with a cough.

Aaron's practical joker college roommate arrives for a visit and announces that he wants Aaron to marry his widow, Aaron's former girlfriend, when the malignant and inoperable tumor in his brain finally takes his life in a few weeks; Keith and Danny continue to clash; Aaron runs into an old friend as he stumbles home after a night of drinking with his college roommate; Gina has a miscarriage, but a grieving Keith wonders if it wasn't deliberate; Karen suspects that Jack's gambling again, an accusation which he denies; Maricela puts the moves on Aaron; Karen is wary when Jack finally comes to her for help.