The Devouring by Simon Holt begins with a prologue from the point of view of young Macie Canfield. Macie's younger brother is being punished for not putting the cows in the barn. Their drunkard father hangs Jeremiah from the scarecrow pole in the field as a punishment. Jeremiah is afraid and is soon attacked by the Vours, a group of entities that feed on one's fears.

The story shifts to 15-year-old Regina Halloway reading a story to her eight-year-old brother Henry. Reggie loves horror stories and shares them with Henry who often becomes frightened. Reggie and her mother had shared the same bond and Reggie wants to carry on the tradition, especially now since their mother has disappeared.

Reggie and her best friend Aaron are horror buffs. The heart of the story begins when Reggie finds a journal written by Macie Canfield, a local woman whose brother had been attacked by Vours. Reggie and Aaron are fascinated by the tale but certainly do not believe it.

Reggie and Aaron consult Reggie's boss, Eben, owner of Something Wicked, a bookstore. Eben is a mysterious creature who says little but repeatedly warns the friend not to take things so lightly. Eben warns the friends that sometimes one can make something become true simply by believing in it. Reggie and Aaron do not heed Eben's words.

Things change drastically when Reggie and Aaron summon the Vours. The Vours do not attack Reggie or Aaron but rather the young Henry, who is much more susceptible to the fear.

Reggie and Aaron must find answers regarding the Vours and discover a way to save Henry from eternal doom.

Reggie, Aaron and Eben go to the Canfield house and find the body of Jeremiah Canfield, who had been boarded up in a room in the cellar. There, Reggie gets her first face to face meeting with a Vour. The trio escapes from the house. Reggie returns later, determined to kill the Vour with cold. Meanwhile Reggie's crush, Quinn, who is also a Vour, sets the house on fire and Reggie barely escapes alive.

Reggie is thrown into her fears and must also face the fears experienced by Henry if she is going to be able to save him. The only way to vanquish a Vour is to freeze it. After a struggle between Aaron and Quinn, Quinn drowns in Cutter's Lake. Henry is saved from the Vour that had attacked him.

Eben gets rid of Quinn's car and hints that he has had a great deal of experience with the Vours. Henry is rushed to the emergency room for treatment. The reader can surmise that there is a sequel to follow.