Mystery Mansion (1984)

Susan and her brother Johnny go to spend the summer with their aunt and uncle where they discover a map that may lead to some sort of treasure. Susan had been having nightmares about a girl (Rachel) who disappeared in a nearby mansion now old and abandoned. Eventually Susan and Johnny along with their cousin Billy begin a quest to find the treasure as well as the answers to Rachel's disappearance. While they are doing this 2 escaped convicts are also looking for the same treasure!