HIDDEN STAIRCASE
Helen and her great aunt Rosemary ask Nancy to solve a mystery at her great-grandmother's home, Twin Elms, a stately Colonial mansion in nearby Cliffwood. Odd things, beyond the eccentricities of the elderly Miss Flora, are happening. In the meantime, Nancy's father is being threatened by crooked lawyer Nathan Gomber, who feels Carson, as attorney for the railroad, cheated property owners near a new railroad bridge. His client, Willie Wharton, is holding up proceedings by hiding. Nancy and her father view the railroad bridge after church, and must swim to safety to escape a runaway truck at the site.