[2] After the Carnegie Prize win, the book was the focus of controversy due to its depictions of violence and its purported nihilism.

Six people, all from different backgrounds mysteriously find themselves in an underground bunker where there are no windows and no way to escape but the elevator that brought them there.

Teenager Linus Weems wakes up in an underground bunker, having been drugged with chloroform and kidnapped by a stranger.

Although Linus is from a wealthy family, since the death of his mother and subsequent arguments with his father, he had run away from school and been living on the streets.

Jenny successfully convinces the kidnapper to send down food by presenting a polite, handwritten note to 'Him' via a message in the lift.

Other kidnap victims arrive: Anja is a woman in her twenties; Bird is an older businessman; Fred is an addict; Russell is an elderly man with a brain tumor.

The group quickly learn that any attempt at escape results in 'punishments' from the kidnapper, such as deafening noise being played, being knocked out with gas and food deliveries stopping or being poisoned.

Desperate for escape, Linus attempts to lure 'the man upstairs' into the bunker, but the kidnapper sends down a vicious Doberman pinscher in the lift instead.

Anja is strangled to death by one of the group – the killer is never identified but is strongly presumed to be Bird, whose injuries are causing him to act strangely.

The kidnapper continues to play games by sending a note, falsely implying that Linus committed the murder to create suspicion.

[4] Kirkus Reviews gave a starred rating, writing "Not for everyone, this heady novel is worthy of study alongside existentialist works of the 20th century.