Benton decides to blow the whistle on Vucelich's unethical study methods, causing Vucelich to drop him from the study. Susan treats a street couple, one of whom has passed HIV to the other. Doug receives a visit from his estranged father. Carter spreads rumors about an affair between Mark and Susan. Mark buys a motorcycle. Prostitute Loretta has cervical cancer.

Susan throws herself into her work to escape her stressful personal life, earning recognition from Kerry and Mark, who begins preliminary discussions on next year's chief resident. Carter needs a pedes rotation, and fast, with Doug to graduate med school. Doug takes up with his father's girlfriend. Shep overreacts and attacks an Asian boy interfering at a scene. Mark and Jenn try to discuss their divorce amicably, with unforeseen results. Benton is named Resident of the Year. Harper leaves for an OB rotation at Parkland in Dallas.

While Mark is anxious about Susan's return from her holiday, Doug and Carol ride along with the health mobile.

Benton goes into Carla's private hospital files when he fears that something may be wrong with their baby; Jeanie treats a suicidal woman who reveals a surprising secret; and Greene learns that Rachel has been lying about her health.

It's Carol's birthday, Mark is returning to work after being assaulted and Carla goes into premature labor.

His ex-wife Jennifer tells Mark he can't see Rachel until he's got his act together. Reece gets to go home. Al has lost his job.

Jeanie believes she's been fired because she has HIV and fights her dismissal.

Jeanie fears Scott Anspaugh's cancer may have returned. Hathaway learns a disturbing secret about a 16-year-old girl. A pregnant patient fears she'll miscarry; Morgenstern returns to work, but perhaps too soon after his heart attack.

Amanda Lee's obsession with Dr. Greene comes to a head when Mark inadvertantly digs up old med school records damaging to her career. Carter tries to save Lucy from Edson's advances. Peter treats Dr. Parks' grandchild, who interprets for her deaf mother and grandmother. Police officer Reggie Moore asks Jeanie out. Kerry receives a call from someone claiming to be her mother. Doug receives a job offer from Portland.

Benton struggles with the idea of taking a DNA test to determine whether or not Reese is actually his son. As the signs continue to pile up, Kerry and Mark use a fake patient to convince Dr. Lawrence of his Alzheimer's. Carter has trouble persuading a woman from a nursing home fire to sign a DNR for her husband and later is asked to forge charts for a family with no insurance. Carol continues to meddle in Meg's life, having her arrested so that she can be detoxed. Cleo is blamed for an explosion in the suture room but it may actually be Dr. Dave's fault.

Two boys brought in after a fight at school leads Cleo to discover that one of them has been injecting himself with hormones. Hathaway's obstetrics nurse, Abby Lockhart, joins the ER as a third year medical student on an ER rotation.

Carter seeks psychiatric help because he can't sleep. He then visits the wife of his attacker. Weaver returns to work after her suspension. Hathaway and Kovac share a kiss.