Ollie is an 11-year-old girl living in East Evansburg, Vermont. Following her mother's fatal plane crash, she withdraws from the chess club and softball team. She avoids her classmates and prefers to hide near Lethe Creek to read in silence. Her sharp intellect makes her an excellent student, but she actively pushes away anyone who tries to offer sympathy.

Brian is a popular middle school student and the star player for the local hockey team. He has Jamaican heritage and lives in the rural town of East Evansburg. Although Ollie dismisses him as a typical jock, Brian reads classic literature and surprises her by quoting lines from *Alice in Wonderland*. He covers for Ollie when she gets into trouble with the principal.

Coco is a new transfer student in the sixth grade. She has striking strawberry-blond hair and ice-blue eyes. Her squeaky voice frequently irritates Ollie. Coco easily displays her emotions and cries when overwhelmed. She has a background in rock climbing and tries hard to make friends in her new environment.

Seth works as a handsome, easygoing farmhand who milks cows and guides the visiting sixth-grade students. In the antique diary Ollie reads, the smiling man is described as a terrifying supernatural figure who approaches vulnerable people in the mist. He grants their deepest wishes in exchange for terrible bargains.

Mr. Jones is a farmhand at Misty Valley who fills in as the substitute bus driver for the school outing. He has a thick gray beard and unnervingly red lips. His pale, mushroom-colored skin makes him look unhealthy. He recites creepy nursery rhymes about missing brothers and watches Ollie closely.

Mr. Easton is a patient middle school teacher in East Evansburg. He worries about Ollie's isolation and gently tries to push her back into the chess club. During the field trip, he enthusiastically shares the local ghost stories and history of the Misty Valley Farm with his students.

Linda owns Misty Valley Farm, a local property with a dark history that she runs as an eco-tourism destination. Ollie first meets her acting erratically by the local swimming hole. Linda claims she has no choice but to follow the instructions of a mysterious bargain. Later, she acts completely normal while hosting the students.

Beth is a 19th-century farm owner who wrote a warning letter to her daughter. Her written accounts describe her early romance with a hired farmhand and the subsequent tragedies that struck her family. Her diary serves as Ollie's primary source of information about the history of Smoke Hollow.

Ollie's father is a nurturing man who enjoys domestic hobbies like cooking and pottery. He paints their home bright colors, earning it the nickname "The Egg." Following his wife's death, he takes on all parenting duties. He packs massive lunches for his daughter and tries to understand her moody behavior without pushing too hard.

Ollie's late mother was a fierce, adventurous woman who loved the outdoors. She died in a small plane crash a year before the main events of the story. She taught her daughter to be brave and practical in emergencies. Ollie carries her broken altimeter watch everywhere.

Phil is a tall, gangly sixth grader who delights in playing disruptive pranks. He specifically targets the new girl, Coco, mocking her personal drawings to get a laugh from the rest of the class. His bullying prompts Ollie to throw a rock at his friend's head.

Jonathan is a historical figure in Beth's diary. He arrives at Smoke Hollow in the 19th century and eventually marries the farm's heiress. When his brother disappears following a violent argument, Jonathan experiences overwhelming guilt and searches the misty woods for him.

Caleb is Jonathan's brother in the historical accounts of Smoke Hollow. He harbors jealousy over his brother's romance with Beth. Following a bitter dispute, he runs off into the woods, setting off a tragic chain of events. When he eventually returns, he acts hollow and detached.

Cathy is a historical figure from the 19th century. She travels to Smoke Hollow with her two sons to find employment and shelter. Her life revolves completely around the well-being of her boys.