"To claim her inheritance, Helen Vaughan must spend one year in her ancestral home, Harrowstone Hall, and with her life and sanity at stake, she must unravel Harrowstone's secrets, an endeavor that forces her to question everything she knows about her family and herself." --

After years in foster care, April gets to live in a mansion where she and four other children are caught up in a mystery related to a missing heir, a lost legacy, and the Phantom. --

Seda, sixteen, feels her invisible childhood nemesis, Sawyer, growing stronger just as a group of stranded teens takes shelter from a blizzard in the dilapidated mansion Seda's mother inherited. Seda's mom inherited an old, crumbling mansion, and it was fun to explore the beautiful grounds for a summer. When her mom decided to renovate and live there, Seda isn't happy. And the coming of winter they'll be cut off from the outside world. When a group...

"Clara Starling lives a life of dull rules...until the day Uncle disappears, leaving Clara alone in his old mansion. When streetwise orphan Peter and his rescue cat arrive unexpectedly, the children seize the chance to live by their own rules. But when the pair's wild romps through the halls of Braithwaite Manor reveal a single, worn ballet slipper, they are hurled into a mystery that will lead to London's glittering Royal Opera House and the unraveling...

When their parents divorce, twelve-year-old twins Felix and Maisie move with their mother to live in the attic of a historic Newport, Rhode Island, mansion where they discover a hidden room that carries with it an intriguing secret.

Nancy Drew and her friends attempt to solve the mysteries surrounding ghostly performances of a life size puppet and the Footlighters acting group.

A banker who has been receiving threatening notes enlists the help of the Hardy boys. Before very long, the young sleuths find themselves entangled in the investigation of a notorious band of thieves.

"When twelve-year-olds Hannah and Maggie switch places, Hannah must prevent a famous art theft in 1905 and Maggie must cope with modern life until they can switch back." --

"In this partially illustrated early chapter book, ten-year-old nonbinary Sly works to solve riddles and locate the spell that can save them, their grandmother and a ghost girl from being stuck forever in an enchanted mirror"--

When Tommy goes to visit his Aunt Jeanne at her mansion, he finds a series of notes that are clues to an unnamed puzzle meant to be solved by Tommy and the reader.