Megan Sullivan is H.I.V. positive, pregnant and missing. Initially the team suspects that her husband, who seemed to be less than thrilled about the baby, is involved, but soon learn that Megan had received a call from a prison, and their search tracks them to a former lover, who gave her H.I.V., her husband's former mistress, who had seen her taking part in a tense conversation not long before she vanished, and her own H.I.V. specialist, who had recently given her bad news. Martin thanks Danny for his help, and tells him that he is continuing to seek counseling for his addiction.

The team searches for a fifteen-year-old girl who lived with her grandfather and was last seen at an Internet café. Sam gets an unexpected visit from her estranged sister.