When Will Burrows and his friend Chester embark on a quest to find Will's archaeologist father, who has inexplicably disappeared, they are led to a labyrinthine world underneath London, full of sinister inhabitants with evil intentions toward "Topsoilers" like Will and his father.

"It was supposed to just be a normal basement--some storage boxes, dust, you know, the usual basement stuff. But when Milo is sent by his mother to fetch a sock from the basement of the historic home they've moved into, Milo finds a door in the back that he's never seen before. Turns out that the basement of his house is enormous. In fact, there is a whole world down there. As Milo travels ever deeper into the Basement World, he meets the many Things...