Thornhill follows two girls who live in the same neighbourhood but in different times—Ella who has recently moved into the house across from Thornhill and Mary who lived in Thornhill in the 1980s. Ella's story is told through numerous illustrations as she unpacks her possessions and deals with the aftermath of her mother's passing. Mary's story is told through diary entries as she deals with her inability to speak and the harassment of the other girls living at Thornhill, culminating in a tragedy that haunts the community.
Both stories intertwine after Ella notices a figure standing in the window of Thornhill, which has long since been abandoned. Wondering who it is, she begins to investigate, never quite catching them. Instead she encounters a series of old, worn dolls which provide a sense of comfort to Ella as she restores them to their original appearance. Through the dolls Ella forms a bond of friendship with Mary.
The majority of the book consists of grayscale images—although simplistic in appearance, they convey a sense of emotion and weight. The repetition of imagery across pages gives a sense of movement, almost like one is a watching a film, and creates a haunting, atmospheric feel to Ella’s world. While this technique does slow the pace of the story, it serves to heighten Ella’s isolation and loneliness.
The plot itself is highly engaging, yet slow-paced, with Ella and Mary’s lives mirroring each other through their sense of isolation from others and inability to change their situations. The action picks up as Ella discovers the reason behind Thornhill’s closing, but an unexpected resolution will cause readers to question character’s motivations and what truly happened.
For books similar to Thornhill, Emily Carroll’s short story anthology, Through the Woods, has the same haunting atmosphere while dealing with more overt horror. Brian Selznicks’ novels The Invention of Hugo Cabret and Wonderstruck have the same style of illustrations with accompanying text.