The BAU zeroes in on a twisted UnSub in D.C. destroying his victims by spraying and submerging them in acid. Prentiss and Rossi dive into the BAU's history to see how they are connected to Gold Star. They soon discover that the only backup files available belong to the wife of a former BAU member. Prentiss goes to her to uncover the truth. Voit utilizes his lawyer to reach out to Damien and gain footing against the BAU. (thetvdb.com)