Mystery Up the Winding Stair — Helen Fuller Orton

Harry spends an adventurous three weeks at his grandfather's house. Strange things begin to happen, including sounds in the night, mysterious intruders, and the finding of hidden staircase. All this leads to the surprising climax and the finding of a precious gem.

Four boys and girls in a great country house, with the exciting task of trying to find a mislaid treasure, make the actors scene and plot of this delightful mystery story. The winding stair leads from the library to a circular room so large that it can contain and exact replica of a pioneer log cabin. Harry and Ned, Lou and Carol find the winding stair a fascinating start of a mysterious adventure that lasts through a snowbound winter holiday.