The cover illustration features a wolf howling at night on a green fogging swamp while a torn shirt and a cap are next to the wolf.
The narrator, Grady Tucker and his sixteen year-old sister, Emily, have both moved to a new house with their scientist parents. Their father, Dr. Tucker, studied deer in Vermont until he came into possession of six "Swamp Deer" from South America. Because of this, Dr. Tucker had to move with his scientist wife and the two children to Florida so he could test his hypothesis: Deer can live in Florida. Though he keeps them in a pen in the backyard for now, Dr. Tucker intends to release the deer with tracking collars into the wild.
While lazing around the new backyard, Grady spots a crane with his binoculars and attempts to get Emily to accompany him into the swamp to follow the bird. The two children go exploring in the swamp. Emily learned all about forests and swamps in school, so she fills Grady in on all the scientific details.
Emily and Grady suddenly find themselves lost in the swamp. They wander around, eventually finding a small shack. A crazed white-haired man exits the shack and chases after the two children, who run around until finally they find the door to their house. Once inside, they tell their parents about the wild man. His father tells the children that he is just "a swamp hermit." Then he says that the guys at the hardware store said the swamp hermit is completely harmless.
Later that night, Grady is just kicking it in the backyard when another twelve year-old boy, one of his new neighbors, introduces himself as Will Blake. Will is a big child and tells Grady that the only other child their age on the block is a "weird girl." Will walks over to the deer pen, picks something up, and utters "Yuck. Deer slime."
Will tells a story about how Fever Swamp got named. A hundred years ago, everyone in town caught something from the swamp that started with a fever and most died and those who did not die went crazy. Late that night, Grady comes down with a fever. Woken from a fever dream, Grady hears howls coming from outside. He goes down to the kitchen to investigate and hears scratching on the exterior door. Emily wakes up too and the two siblings sit in the kitchen, listening to the howls and scratching at the door. Grady bravely opens the door but sees no one outside, and since it is midnight, does not go outside to investigate further. The two siblings listen to the sounds some more and then their father wakes up and insists on taking both of their temperatures.
The next morning, no sooner does Grady leave the house than he is attacked by a lovable but huge 100lb dog. The dog starts licking Grady's face and Emily comes out and pets the dog, figuring this is the source of the scratching from the previous night. After some discussion, the parents decide that a dog would be fine to let into their house.
Will shows up to go investigate the swamp with Grady, and suggests to the family that the dog might be part-wolf. So they name the dog, Wolf. The two boys leave the dog at the house and are not in the swamp for more than a few minutes before Wolf shows up and accompanies them into the thicket of foliage. They fool around the swamp for a while and then Wolf starts growling as he spots the Swamp Hermit. Will thinks the Swamp Hermit, whose shirt is covered in blood, might be dangerous. They remain still as the Swamp Hermit quietly leaves their line of sight.
As soon as the coast is clear, the boys continue exploring and come across a mauled heron. The bird has been ripped apart and there are paw prints around the body. Grady guesses a dog did it but then Will tells Grady that dogs do not rip apart birds. Will goes back home and Grady enters his house. Dr. Tucker tells Grady that the swamp is filled with scary stuff and that another bird probably killed the heron.
The entire family is awoken in the middle of the night by crashing from downstairs. They all huddle together and make their way down to investigate. The noise was caused by Wolf, who has run around the living room, smashing into the furniture in a desperate attempt to get out of the house. Dr. Tucker gets especially dismayed when he discovers the dog had broken the lamp. The dog starts ramming its body into the plate glass sliding door until finally the father opens the door and Wolf leaps out of the house into the swamp. The family goes back to their rooms, but before long, Grady hears howling coming from the swamp again. In the light of the full moon, Grady can make out a four-legged creature in the shadows below his window. The creature leaves something resembling a rag at the foot of the deer pen and leaves. Grady goes down to get a closer look and sees a chewed up rabbit.
The next morning, after breakfast, Grady takes his father to see the dead rabbit. Wolf shows up and gently licks the child's face. Emily is convinced that Wolf killed the rabbit and pleads with their father to get rid of the dog. Grady tells her she has no proof that the dog killed the bunny. Emily says there is no proof he didn't either. Will shows up and tells Grady that a neighbor, Mr. Warner, has gone missing. Apparently Mr. Warner left early the day before to go turkey hunting in the swamp and never returned. A voice from behind them suggests that a werewolf did it. That voice belongs to a redhead named Cassie O'Rourke, the weird girl Will mentioned. Will tells her to shut up, that what she is saying is stupid. Cassie presses the issue and tries to convince Grady that the howls can only be made by a werewolf that has made a fresh kill.
Cassie freaks out when she sees the Swamp Hermit in the distance, yells and points at him. The Swamp Hermit has a wild turkey slung over his shoulder, leading the children to wonder if he swiped it from the missing Mr. Warner. The Swamp Hermit is close enough to hear these accusations and runs out of the swamp towards the children, yelling "I'm the werewolf! I'm the werewolf!" over and over, cackling all the way. The other children flee, as the hermit grabs Grady's ankle, keeping him in place. The old man just cackles and waves at him with his free hand and tells Grady he was only playing. Wolf trots up and barely acknowledges the hermit, who lets Grady loose from his grip. The Swamp Hermit tells Grady to be careful about his dog and heads back to his shack. Then Grady gets bitten by a snake.
Wolf leads Grady back to safety and he tells Will and Cassie, who have regrouped on his lawn, to get his parents. Cassie tells Grady's mother that he was bitten by a werewolf. Grady's mother puts an ice pack on Grady's ankle and jokingly tells him that his father is a werewolf and that she shaves his back every day so he will look normal. Grady persists that a werewolf could be responsible for the events in the swamp, like the howls. The mother replies that a lot of things howl in the swamp, even Grady when he got bitten.
Dr. Tucker tells Grady that since the moon will only be full for two more nights, they will know after that whether or not the howls came from a werewolf. Then he too starts laughing, as he said it to mock his son. The mother picks up a newspaper and shows her black newsprint hands to Grady and tells him it is hair that's grown on her palms. Emily suggests that the dog is the werewolf.
Cassie and Will come over that night to eat and after dinner Grady sits with the two as they trade barbs about just who in this book is the werewolf. This quickly turns into the two just calling each other names while Grady watches. Then each accuses the other of being the werewolf.
Lying in bed, trying to sleep, Grady hears the howls from outside again. Then he hears a commotion below his window again. This time when he goes to investigate, he find one of the six "swamp deer" mauled, the other five deer huddled together in their pen, away from the gaping hole in the metal. Grady calls his father down from the lawn to see the corpse. Dr. Tucker patches the pen with a piece of cardboard.
After dragging the dead deer to his workshop, Dr. Tucker tells his son that clearly his dog is a killer. Grady's father tells him that tomorrow morning, he is taking the dog to the pound to be killed.
The next morning, Grady's father tries to take Wolf to the pound but Grady tells his dog to run away and it does. Grady's father tells him that was dumb, because the dog is bound to come back, and when it does, he is going to take it to be killed.
Wolf manages to stay out of sight all day and it isn't until late that night that Grady spots him from his bedroom window, lingering at the swamp clearing. Grady goes down to greet his dog and runs into Will. Will claims to have heard the howls and was trying to investigate, when he ran into Grady. The two boys spot Wolf, who has edged back into the swamp. Grady runs after him, losing Will in the process. Following his dog, Grady ends up at the Swamp Hermit's hut. He hears the horrible howling coming from near the shack and he believes that the hermit was the werewolf.
Soon, Grady finds out that Will is the Werewolf, the hard way. He gets bitten in the shoulder by him. Luckily, Wolf comes and fights off Will saving Grady's life. But Grady eventually passes out.
When he comes to, he finds himself safely inside his own home. Grady's father tells him that the Swamp Hermit found him and carried him home. Grady's father also stated that the Swamp Hermit saw Wolf fight off a large creature to save Grady's life. Grady's father submits that they can keep the dog. After listening to Grady's werewolf story, Dr. Tucker figures he might as well try to see if his son could be telling the truth, so he goes to visit Will's house. He finds the house is empty, abandoned, as though no one had lived there for months.
All that happened over a month ago, as Grady narrates it. Grady is so happy that he got to keep Wolf around, because the dog makes for an excellent companion on nights when the full moon is out as Grady became a werewolf when Will bit him.
The Werewolf of Fever Swamp was first reprinted in September 2003. It received a second reprint in October 2009 as the eleventh book in the Classic Goosebumps series, and as a tie-in to the eleventh Goosebumps HorrorLand book, Escape from HorrorLand.
The book was adapted as a comic book in the Goosebumps Graphix book, Creepy Creatures and Slappy's Tales of Horror. It is the first Goosebumps book to be adapted into a comic.
The Werewolf of Fever Swamp was adapted into a two-part episode of the Goosebumps TV series. Part one was the eighteenth episode, and part two was the nineteenth.
Will Blake (in his werewolf form) appears an antagonist in the Goosebumps film. The title of the book is mentioned by R.L. Stine when referring to Will Blake. The original cover art is also featured in the end credits animation.
Cover art gallery
- Night in Werewolf Woods references this book in the form of a question for the reader. However, unlike other Give Yourself Goosebumps books, the question only exists for the reader, and not for his/her character, so it may take the reader out of the story.
- Grady and Emily's father was mentioned by name in the book: Michael F. Tucker.
- In France, this was the 13th book in the series.