Horrid

From the author of You Must Not Miss comes a haunting contemporary horror novel that explores themes of mental illness, rage, and grief, twisted with spine-chilling elements of Stephen King and Agatha Christie.
Following her father's death, Jane North-Robinson and her mom move from sunny California to the dreary, dilapidated old house in Maine where her mother grew up. All they want is a fresh start, but behind North Manor's doors lurks a history that leaves them feeling more alone . . . and more tormented.
As the cold New England autumn arrives, and Jane settles in to her new home, she finds solace in old books and memories of her dad. She steadily begins making new friends, but also faces bullying from the resident "bad seed," struggling to tamp down her own worst nature in response. Jane's mom also seems to be spiraling with the return of her childhood home, but she won't reveal why. Then Jane discovers that the "storage room" her mom has kept locked isn't for storage at all -- it's a little girl's bedroom, left untouched for years and not quite as empty of inhabitants as it appears . . .
Is it grief? Mental illness? Or something more . . . horrid?