The Vanishing of Betty Varian

This is a mystery novel that revolves around the disappearance of Betty Varian. This novel also features Pennington Wise and his assistant to him, Zizi. Headland Harbor in Maine, and in particular the house known as Headland House, which is situated on a promontory overlooking the sea. There appears to be only one way to get to this house, and that is up a road that ends at the lodge and a high wall. Because of its location, the rest of the land is cut off. But when a picnic is planned, Betty Varian needs to return to her house for her camera, and when she is gone for an extended period, her father returns as well. But, as we soon discover, Betty has vanished, and her father is dead on the floor.