The Wishing Well: A Mystery Detective Classic By Mildred A. Wirt!

Wishes made at a well on an old abandoned estate are mysteriously granted, and Penny searches for the explanation. In addition to magical qualities, the well appears to have a tangible hidden value since the property owner is seen searching the vicinity, and a neighbor tries to buy the land. Penny investigates and discovers not only the secret of the well but also a valuable treasure.