When Dr. Gilbert Foster, purchases a towering mansion in west Little Rock, Arkansas the mystery begins to unfold. Rumored to be inhabited by ghosts, the long unoccupied mansion had also been known for mysterious sounds and strange lights at night that disappear when followed. With their ever present curiosity, the Foster twins are determined to learn the secrets of Essex. Suddenly they heard a scream coming from the direction of the Essex. "That's coming from the house " The twins and Dylan hurry to the back of the house. "What happened?" Sydney asks in alarm. Mrs. Affenbaker, is staring out the window in back. "Someone just threw something in the back door " She exclaims. Mrs. Affenbaker is noticeably trembling. "What is it?" she shudders as she points to an object on the floor. Taryn walked to where the strange object lay. "It looks like a human skull." Sydney said. "What do you think, Taryn?" "If it isn't someone has sure made up a very good fake." The twins invite their older cousin Dylan to help them investigate the mysterious mansion. During the investigation, the twins and their cousin run into a hooded, knife throwing figure that seems to disappear as quickly as it appears. With the discovery of a skull, an arrow that narrowly misses Dylan, and a mysterious black sedan constantly on their trail, the cousins and their adventurous mom have all they can handle in this fast paced mystery. The Foster twins are SIXTEEN years old, and full of energy and curiosity. Both twins are a bundle of energy, and are encouraged by their adventurous mom to get involved in mysteries and adventures. In this Mystery of the Haunted House she wonders if maybe she has encouraged the adventures too much. There are bloody skulls, a knife thrower, a mysterious neighbor, a hooded fugitive, a car that disappears, a giant dog with an appetite for teen-age girls, and a scary old man on an island. Are there really ghosts inhabiting the old log mansion?