The Mysterious Key is a classic mystery novel by Louisa May Alcott. Trevlyn lands and Trevlyn gold, Heir nor heiress e'er shall hold, Undisturbed, till, spite of rust, Truth is found in Trevlyn dust. "This is the third time I've found you poring over that old rhyme. What is the charm, Richard? Not its poetry I fancy." And the young wife laid a slender hand on the yellow, time-worn page where, in Old English text, appeared the lines she laughed at.