Jacob Wilkins, Graham Hale Jr., Collie Jackson, and Roland and Pauleen Walker have been kidnapped. Cast through the house of teeth, they've been stranded at the edge of the Void Below. The Abyssal Tide would have crushed them into Voidlings if not for the plucky little Aeln, Yurt. But while the bear is confident he can take the kids home, the sleeping realm of Bahim proves far wilder than any of the Waking could ever know. Thrown from nightmare to nightmare, the children seem to have no choice but to put their fates in the hands of a strange man wearing a clown mask.

Meanwhile, the adults struggle to find the children while being contested at every turn by their personal demons, and by demons unfamiliar. Stripped of his weapon, Dr. Rutherford has nothing but his wits to keep him alive. Stripped of his company, Samantha Hale has nothing. While nightmares hunt the two of them, the rest become nightmares and turn against them. Dentium makes beasts of men and sets Eugene, Ben, and even Gregory himself on the hunt for the children reserved for the Void.

In this conclusion to The House of Dentium, it's a desperate race to find the way back home. Adults and children alike are but sheep among wolves in The Valley of Sleep.