Answer: nancydrew

AnswerCrossword Clue
NANCYDREW"The Secret of the Old Clock" sleuth
NANCYDREW"The Clue in the Crossword Cipher" solver
NANCYDREW"The Bungalow Mystery" solver
NANCYDREWCharacter who first appeared in "The Secret of the Old Clock"
NANCYDREWAmateur detective in 1967's "The Clue in the Crossword Cipher"
NANCYDREW"The Hidden Staircase" sleuth