In 2007, a writer named Lawrence Spencer opened an envelope he didn't ask for. Inside were military documents from Roswell Army Air Field, dated 1947. Duty rosters, memos, Top Secret stamps. And buried near the bottom, transcripts of interviews with a subject the US Army couldn't communicate with using any conventional method. No translator worked. No known language matched. The only person who could reach the subject was a nurse named Matilda MacElroy — and she did it without saying a word....