The Hollow Boy, published in 2016, is the third of a total of five books in Jonathan Stroud's "Lockwood and Co." series. As with previous novels in the series, The Hollow Boy follows the namesake Lockwood and Co., a group of young people who work together to eliminate spirits. One day, supernatural spirits begin to plague London and surrounding areas. Law enforcement doesn't know what to make of the infestation; protests around the city begin to pop up to express their disgust with the spirits and the police's handling of the outbreak. Lockwood and Co. set out to solve the infestation and start to battle against other spirits who haunt various places around the city—including in homes and even more shockingly, in department stores. To make matters worse, assassins start to attack the group and people across the city, complicating matters for the people in Lockwood and Co.
The Hollow Boy will soon be adapted into a television series by streaming giant Netflix. The popularity of the novels reflects this fact: each novel was a bestseller and received exceedingly positive reviews. When it was published in 2016, The Hollow Boy, like the previous novels in the series, received extremely positive reviews. Booklist.com thoroughly enjoyed Stroud's novel, which said that "Stroud writes with a fine ear for dialog, a wry sense of humor, and a knack for describing haunted places. Creating tension that ebbs and flows, he slowly builds the dramatic narrative to a resounding crescendo, and he makes the quieter scenes that follow just as compelling."