Millie Muldoon & the Case of the Halloween Haunting. Millie Muldoon Mysteries, #3

It's nearly Halloween and Great Aunt Priscilla Palermo has a problem. She and her two next-door neighbors have developed a bad case of ghosts! Not the paper, cloth, wood, or plastic kind. The real thing! Spirits of the dead! Spooks that float through the air and scare you to death when they go Boo! They appear in their yards every night after midnight. The ladies may lock their doors and windows. But that doesn't stop the ghosts.
They manage to sneak into their houses anyway. The women can hear them in their basements, walls, and attics. Scratching and shuffling. Creaking and clanking. The elderly ladies are scared to death. Afraid to stay alone in their own homes. They try calling the police, but the cops don't believe them. They insist they're seeing things. But are they? Millie Muldoon doesn't think so. Whatever is happening at her great aunt's house, it's Millie's guess it's not supernatural.
She's convinced the nightly haunting has something to do with tales of underground tunnels and buried Civil War gold. Aided by a team of pint-sized assistants, Millie is determined to find enough evidence to crack the case and send the ghosts packing.