A hospital emergeny preparedness drill turns deadly when an unpopular and ambitious nurse is found dead amid the chaos with an eccentric artist the only witness.

When a rash of deaths at a high school revolve around one 'helpful' young girl, Dr. Sloan risks his own life to uncover the murderer.

Dr. Travis gets involved in the treacherous and deadly trade of catering when he oversees the annual charity banquet.

Mark, Steve, Jesse, and Amanda are all trapped in the rubble of Community General in the aftermath of the bombing. Mark tries to shake off the numbing effects of the explosion in time to save Amanda, who's suffering from a punctured lung and broken collarbone. After the dust settles, the hunt for Caitlin Sweeney begins. It's discovered that the Sweeneys belong to a terrorist organization, R.O.A.R.

Carter and Caitlin kidnap Mark, forcing him to mastermind a 100 million-dollar theft. On the outside, Steve and Ron collaborate to find Mark. Meanwhile, Jesse and the Sloans buy a barbecue joint.

The hospital is the scene of a manhunt when a corpse comes to life and attacks Amanda, then leads Steve and the police on a chase throughout the entire building during which he kidnaps Jesse's girlfriend Steve. Mark learns the fugitive is on the run from NSA agents, who claim he's an international terrorist.

Amanda enlists Jesse's computer-nerd friends to find a killer, after she accidentally surfs across an on-line murder. Meanwhile, Jesse's girlfriend, Susan, comes down with a case of food poisoning after dining at Barbecue Bob's.

Jesse saves a woman, Chloe, in a traffic accident that claims a jealous lover forced her off the road. Jesse looks out for his patient when her ex-boyfriend threatens her. Jesse rushes to Chloe's aid when her life is threatened by her boyfriend, and inadvertently kills him. Jesse finds himself the victim of Chloe's 'fatal attraction' as she pursues him voraciously. It gradually becomes clear that Chloe was the aggressor in her previous relationship.

Dr. Sloan crusades to keep a physician-assisted-suicide advocate from practicing her trade.