Curator of paleontology Dr. Simon Nealy never expected to return to his Pennsylvania hometown, let alone the Hawthorne Museum of Natural History. He was just a boy when his six-year-old sister, Morgan, was abducted from the museum under his watch, and the guilt has haunted Simon ever since. After a recent breakup and the death of the aunt who raised him, Simon feels drawn back to the place where Morgan vanished, in search of the bones they never found.

Curiosities opens with a present-day amateur historian, Anne, who describes her unexpected discovery of five seventeenth-century manuscripts that, astonishingly, tell the same strange story from vastly different points of view. The five manuscripts spin this tale: after the Plague descends upon a village in England, two small children, Joan and Thomasina, are the only survivors.

When Ralph and Abby Lamb move in with Ralph’s mother, Laura, Abby hopes it’s just what she and her mother-in-law need to finally connect. After a traumatic childhood, Abby is desperate for a mother figure, especially now that she and Ralph are trying to become parents themselves. Abby just has so much love to give—to Ralph, to Laura, and to Mrs. Bondy, her favorite resident at the long-term care home where she works. But Laura isn’t interested in bonding with her daughter-in-law. She’s venomous and cruel, especially to Abby, and life with her is hellish.

Every day, Mary wakes up before dawn to make breakfast from scratch. She tends the garden and feeds the animals. Every night, Mary makes sure she has dinner on the table for when her husband Cal gets home from work. She puts on his favourite lipstick and greets him with a smile. 'I've missed you.' It's not true and he knows it. But he likes to hear it all the same. Their cabin is hidden deep in the woods in the Scottish Highlands, and Mary doesn't remember the last time she saw another living soul. She tries not to think about her life before too much.

In a quest for a simpler life, Helen and Nate have abandoned the comforts of suburbia to take up residence on 44 acres of rural land where they will begin the ultimate, aspirational do-it-yourself project: building the house of their dreams. When they discover that this beautiful property has a dark and violent past, Helen, a former history teacher, becomes consumed by the local legend of Hattie Breckenridge, a woman who lived and died there a century ago.