S4, E19: The team members search for a pregnant, HIV-positive woman, Megan, who vanished moments after she and her husband saw the ultrasound of their healthy late-term fetus. They remain wary of Megan's husband, Brian, who allegedly left for a business trip after the ultrasound. Their suspicions are heightened when they learn that he had a brief affair last year after Megan was diagnosed with HIV, which she contracted during a previous relationship. But the investigators also find out that a blood technician had chastised Megan for putting her child at risk by becoming pregnant. They also probe whether or not Megan'sdisappearance is connected to an attempted infant abduction at the same hospital three weeks prior, and they look into the relevance of her last incoming cell phone call from a detention center.