After several of Bailey's patients die, she becomes the focus of a CDC investigation; Cristina teases Alex about his feelings for Jo; Owen continues to take care of Ethan while his parents remain in the hospital.
Kirsten doesn't want Ryan permanently, so he buys a bus ticket. Ryan, Seth and Marissa hide in a model home, but Summer finds out and causes trouble with a bully who fights Ryan.
Carrie reminds Doug of a past incident at their first house when he wants to buy a chainsaw from an infomercial.
While visiting Mexico with her family, a woman becomes a victim of foul play; when the International Response Team investigates the woman's husband, he flees, making him the prime suspect.
Shore defends a man who was fired from his post as Santa at a local department store for being a transvestite; Lori faces an ethical dilemma when her therapist asks her for advice on one of his patients.