Abby Grant thought the summer's adventures had ended with her last day as an intern at Uncle Rick's detective agency. She never imagined they would follow her to a vacation in the lakes region of New Hampshire. Yet she no sooner arrives at her family's Lake Winona cabin than her uncle leaves her an unsettling voicemail, and Abby is torn between telling the truth to her brothers and friends about his suspicions, and not wanting to worry them. She stumbles upon a mysterious old letter and suddenly finds herself face to face with her nemesis Neil DeWitt, entangled in a mystery surrounding a Cold War diary, a missing dossier, and a kidnapped treasure hunter. Can Abby solve the scrambled clues before time runs out? Beyond that, can she find the courage to confront her dilemmas and begin to forgive the one who has wronged her? What weighs in the balance is worth more than even the secrets that lie somewhere beyond Lake Winona's shore.