The team investigates an unsub with striking similarities to "The Chameleon."
After Cuddy's mother (Candice Bergen) complains of unusual symptoms, she is admitted to the hospital; Masters questions her principles.
Following an encounter with Lynch, Dr. Reid suffers from a brain injury and is visited by ghosts from his past. The BAU makes a discovery about Lynch that affects Rossi personally.
The BAU team investigates a series of seemingly random fatal explosions throughout Kentucky and Tennessee.
When packages with gruesome contents are delivered to six people in the Washington, D.C. area, the BAU must first figure out what connects the recipients before they can identify the UnSub. Also, Simmons and Kristy (Kelly Frye) struggle to connect with their son, David, who is suspended from school for aggressive behavior.
