Back from maternity leave, Chen (Ming-Na) returns to the ER just as the staff is confronting a somewhat startling case of the measles. In other developments, Benton (Eriq La Salle) offers to act as mentor for African-American medical student William White (Keith Robinson) -- until he finds out the real reason that White was accepted as an applicant. Weaver (Laura Innes) begins to question her relationship with Kim Legaspi (Elizabeth Mitchell). And despite his own deteriorating state of health, Bishop Stewart (John Cromwell) insists upon taking charge of an ordination. ~ Hal Erickson, Rovi