In Bloom

The NIH team hurtles toward St. Louis when four middle-school teens fall ill to encephalitis. Meanwhile, after Connor and Natalie conduct inconclusive tests, they shock the parents when they ask for a brain biopsy to detect if the problem resulted from a sexually transmitted disease. Eva investigates a different path when a friend suggests that the girls were poisoned by a jealous rival -- even as new cases are reported. In addition, Natalie feels helpless to provide comfort for a long-suffering patient (guest star Shea Whigham) who is participating in a clinical trial.