Kelly McCracken

When Dr. Alicia Seberg, a government research scientist (guest star Amy Price-Francis), is exposed to a deadly toxin while at work and has only hours to live, she calls Patrick Jane and the CBI to find her murderer.

Marissa and Ryan begin dating. Summer tries to deny her feelings for Seth as he gets closer with Anna. Kirsten and Sandy continue to clash. Julie reveals a new relationship.

The team searches for a murderer who posts missing-persons fliers of potential victims where they will see them before being kidnapped and killed.

J.D. (Zach Braff) Turk (Donald Faison) and Eliot (Sarah Chalke) quickly become overwhelmed on their first night without the supervision of an attending physician when their newly established authority as residents turns out to be more work than they anticipated forcing them to rely on Carla (Judy Reyes) and even the janitor (Neil Flynn) for assistance. Meanwhile Dr. Cox (John C. McGinley) begrudgingly acquiesces to Dr. Kelso's (Ken Jenkins) request that he introduce him at an awards ceremony fueling Cox's resentment and resulting in a rather unusual presentation.