Having been sent to live with their eccentric grandmother (Granny Relda) in tiny Ferryport Landing, N.Y., orphans Sabrina and Daphne Grimm are now enrolled in school. On their first day at Ferryport Landing Elementary, 7-year-old Daphne learns she has Snow White as a teacher. She loves school, and her positive, carefree attitude endears her to her fellow students. Eleven-year-old Sabrina isn’t so lucky; her teacher is Mr. Grumpner, a crabby, abusive man, who seems to hate everyone, especially children.
The Grimms are descended from one of the famous Brothers Grimm. They are the caretakers of the town and peacekeepers between the Everafters, characters from classic fairy tales and stories, such as Snow White, Rumpelstiltskin, the three pigs and the Big Bad Wolf. A spell put on the town creates an invisible barrier around it so the Everafters cannot leave as long as a Grimm is alive.
The three Grimm females, along with Puck, whom Granny Relda has adopted, are thrust into another mystery when Sabrina and Daphne find Mr. Grumpner dead. The teacher is hanging from the ceiling of his classroom in what looks like a huge spider’s web.
On the second day of school, Sabrina is given detention, and she persuades Daphne to do something to be assigned detention, too. As they enter the detention room after school, they stumble on a horrifying scene: Charlie the janitor is lying dead on the floor. His overalls cover his skeletal remains.
The girls notice Wendell Hamelin, the principal’s son, escaping out of the room’s window. He runs into the woods beyond the school. Along with Puck, who has been sent to school by Granny Relda as the girls’ bodyguard, they give chase. They discover Wendell in the forest, but when he learns they doubt his innocence, he blows on his harmonica and hundreds of rabbits attack the trio. (Wendell’s father is the Pied Piper, and Wendell shares his dad’s Everafter magical powers.) Puck, who can sprout wings, saves the girls by picking them up and flying them out of the woods. Later that night, the three of them and Granny Relda go back in the woods and rescue Wendell.
The next day at school, the sisters, Puck and Wendell, who now fancies himself a detective, search for clues to the mystery by trying to sneak into the boiler room, which is locked. They drink a magic potion from Alice in Wonderland and shrink so that they can sneak under the locked door. While inside, they overhear an ominous conversation between Principal Hamelin and another man about a major event that will happen that night.
The girls tell Granny Relda what they’ve heard. Since they’d disobeyed her by sneaking into the boiler room, she makes the girls stay home with Snow White as their baby sitter. Meanwhile, Granny and Mr. Canis, her chauffer who is also the Big Bad Wolf, head back to the school. The girls find more clues about what might be happening at the school in journals and stories that they read and convince Snow White to take them there.
Sabrina figures out that Rumplestiltskin is behind everything. He has convinced the Pied Piper to use his magical powers to hypnotize the schoolchildren into digging a tunnel that leads from the school’s boiler room and underneath the river so they can escape Ferryport Landing. The spell around the town preventing the Everafters from leaving is not nearly as strong underground.
The Grimms realize, however, that Rumplestiltskin’s plan won’t work. The end result will be the tunnel caving in and burying everyone who is in it. After a long and scary fight in the tunnel — between the Grimms, Puck, and several monsters — Rumplestiltskin is apprehended and the plan is averted.
At the very end of the book Sabrina enters a magic portal, which leads into the room where her kidnapped parents lie sleeping on a bed. A creepy, sadistic young girl wearing a red cloak confronts her. Puck enters the portal to bring Sabrina back, but the portal’s opening closes before either of them can return to Ferryport Landing.