When Judith Chen is found floating in Boston's Harbour, links are made with the murder of Emma Hale, a student who vanished without trace, only for her body to wash up months later. CSI Darby McCormick is assigned to the case and uncovers a piece of overlooked evidence from the Hale investigation - which brings her into contact with Malcolm Fletcher, a former FBI agent now on the Most Wanted list after a string of bloody murders. And when a third student goes missing, Darby is led into a dangerous game of cat-and-mouse with deadly links to the past - and a man who speaks to the Blessed Virgin. A man who wants to be a secret friend to the girls he abducts...