Algernon Blackwood’s “The Willows” is one of the best pieces of horror fiction ever written. In Blackwood’s story, two travelers get lost on a canoe trip along the Danube. They land on an island where the titular willows are everywhere. The travelers soon realize that the plants are reading their minds. The more they think about the extradimensional willows, the more powerful the willows become. (You can read the story at Project Gutenberg for free). It’s terrifying in the story, and equally terrifying in T. Kingfisher’s The Hollow Places, which riffs on Blackwood’s concept.
Kingfisher’s main character, Carrot (Kara with red hair who never shook her childhood nickname), is running her Uncle Earl’s “Glory to God Museum of Natural Wonders, Curiosities and Taxidermy” while he has knee surgery. It’s smooth sailing until she finds a hole in the wall. She convinces Simon, the proprietor of the coffee shop next door, to help her patch it. But when they find that the hole leads to a hallway, they decide to explore. Á la House of Leaves, this hall is impossibly long, going past where the coffee shop should start and where the building should end on the outside.