
The Secret of the Floating Phantom by Norma Lehr, 1994.
Kathy Wicklow is going to be staying with her grandmother in Monterey for a while, helping her while she recovers from a twisted knee. Kathy is disappointed about it because she only just got home from visiting her Aunt Sharon, and she was looking forward to some time at home with her dog, Snuggles. Snuggles can’t even come with her to her grandmother’s house because of her grandmother’s allergies.
Kathy’s grandmother is a dance instructor, but someone else has to teach her classes until she’s better. Her friend, Loretta, owns a Spanish restaurant and sometimes visits and brings dinner with her. (The grandmother describes it as a “Spanish” restaurant, but they serve things like tacos and burritos with salsa, which is what people where I live think of as Mexican food.) Kathy’s grandmother is sure that Kathy will like Loretta’s granddaughter and grandnephew. However, she is strangely secretive about what she and Loretta have been doing during her visits, saying that their meetings, which they hold with a mysterious man called Mason, are financial discussions and are “not for children.”
Kathy learns that her grandmother and her friend are really holding séances. Loretta’s husband is dead, and Loretta fears that she might lose her property unless she can produce the original deed to it. She thinks her husband knew where the deed was, and she hopes to contact him so that he can tell her. When Kathy spies on them during a séance, she sees a mysterious fog that seems to be trying to tell them something. No one else can see it but her. It appears to Kathy several more times, and it seems to be leading her not only toward the deed but toward a lost treasure from the early days of California.
Kathy is suspicious of Mason’s motives and the fact that he doesn’t seem to like her. It turns out that he is not really trying to help Loretta and her family but trying to find a treasure that was hidden by an ancestor of Loretta’s over a hundred years ago. At that time, the area where they now live in California was attacked by pirates. Loretta’s ancestor, Ambrose, was given the task of hiding the treasures from the local mission. He buried them under a tree and marked the tree with a cross. However, during the attack, he was badly injured and blinded. He was unable to find the spot where he buried the treasure himself, and the others who went to find it couldn’t locate the tree.
The fog-like spirit that Kathy sees is Ambrose. Lisa, Loretta’s granddaughter and Kathy’s friend, is spooked by Kathy’s visions, but she helps Kathy to follow the clues that the ghost provides to the treasure. In a hole in the trunk of the tree, Kathy also finds the deed that Loretta has been searching for. Mason tries to take the treasure himself, but he can’t move the heavy bricks on top of it by himself. Mason leaves before anyone can confront him. Digger, Lisa’s cousin, feels especially betrayed because Mason had seemed like such a good friend to him. Kathy notices that Mason seems to share some characteristics with one of the pirates from the attack in Ambrose’s time, which might be a hint that Mason is a descendant of the pirates, but it’s never fully explained.
The book is currently available online through Internet Archive.
The Talking Table Mystery by Georgess McHargue, 1977.