While on vacation in Mexico with Emily, Lightman becomes involved in the case of a missing American woman, who is a single mother on vacation with her daughter. Upon investigation, Lightman learns that the mother got herself involved with an illegal fertility broker and he manages to find her just in time. Back home, Foster investigates D.C.-area hospitals with Lightman’s rival, Jack Rader. They try to uncover the reason that five people have grown gravely ill after receiving blood transfusions.