ER: Season 4
In its fourth season,ERhad its strongest cast yet.  Sherry Stringfield was missed, but British surgeon Elizabeth Corday (Alex Kingston) makes her debut, and Noah Wylie (John Carter) and Maria Bello (Anna Del Amico) made significant strides forward. Carter finds that his move from surgery to the ER has knocked him back to intern status, but he proves himself under fire when the ER is hit by a toxic spill.  He also has plenty to worry about with his addicted cousin, Chase (Jonathan Scarfe), but he's helped by his developing relationship with Del Amico.  Mark Greene (Anthony Edwards) is fighting legal and emotional battles following the previous season's incident, and strikes up a relationship with addled desk clerk Cynthia Hooper (Mariska Hargitay).  Kerry Weaver (Laura Innes) finds her promotion to chief of emergency medicine rockier than expected when she changes her mind on a deal with a cost-cutting firm, which is complicated when she's been seeing the representative (Clancy Brown). She also runs into trouble when she tries to terminate Jeanie Boulet (Gloria Reuben), who ends up staying at the ER and befriending the cancer-stricken son (Trevor Morgan) of Dr. Anspaugh (John Aylward). Peter Benton (Eriq LaSalle) struggles as a new father, develops a rivalry with Corday as he angles toward a spot on the team of arrogant hotshot Rocket Romano (Paul McCrane), and has a career-threatening disagreement with chief of staff Dr. Morgenstern (William H. Macy). Ross (George Clooney) tries a secret romance with on-again-off-again partner Carol Hathaway (Julianna Margulies), whose frustration with patient care leads her to open a women and children's clinic. The season kicks off with the famous live episode, "Ambush," in which a documentary film is being shot at the hospital, and in a continuing storyline, a serial rapist who preys on elderly women forces Carter to make a critical decision.  Guest stars include John Cullum as Anthony Edwards' father, Harold Perrineau as the father of a boy with inverted organs, Dan Hedaya as a lawyer who wants to be a doctor, and Mickey Rooney as an optical patient. Bonus features consist of deleted scenes for a number of episodes, the wrap parties that followed the live show on each coast, and a 20-minute feature on the making of that episode, including some new interviews with the crew.--David Horiuchi