One warm night four children stood in front of a bakery. No one knew them. No one knew where they had come from.

Taking a shortcut through the Greenfield Cemetery, the Aldens stumble across a local superstition which maintains that visitors are required to leave gifts or suffer the wrath of a malevolent ghost, a suspicious tradition that prompts the children to expose the truth.

While visiting a recent purchase of Grandfather's, a ghost town in the Rocky Mountains, the Aldens encounter a mystery involving a run-down motel and a woman who may be a ghost.

In The ghost of the chattering bones, while vacationing at a friend's country home, the four Alden siblings try to find a long-missing, priceless brooch and investigate the existence of a ghostly stream. In The creature in Ogopogo Lake, the Aldens visit Grandfather's friend at the Ogopogo Retreat and aided by puzzling clues, embark on a treasure hunt to prevent the retreat from being sold. In The vampire mystery, when the Aldens agree to watch the...