Orton, Helen Fuller

The disappearance of their picnic items from an unoccupied house leads a group of children to discover mysterious intruders who have been living there.

The teacher's gold dollar that is used for the weekly prize disappears from the little red schoolhouse.

When the money for the wheat crop is stolen from its secret hiding place in the farm house, suspicion rests on the newly hired hand.

Searching for a letter that has mysteriously disappeared from his neighbor's house, eleven-year-old Ken Tracy discovers a hidden staircase, a secret room, and the intruder who uses them.

Four children tasked with searching Professor Barton's large house for a valuable book hidden in a secret room discover they are not the only ones sleuthing.

Unable to find her great-grandmother's diamond ring which she carelessly lost while playing in the orchard, Gloria accuses the new boy of stealing it.