At the hill’s base, Rocco notes the mansion looks black rather than purple. Charlie recognizes it anyway and calls it his house for the first time. Although his friends offer to accompany him, he understands that he must go in alone.

Inside, he finds a green-skinned, mirrored-eyed double of Charlotte making waffles, which were his late mother’s dish for special occasions. Hollow copies of Jack and Andrew sit praising the witch. She tells Charlie his family no longer wants him. Finding no seat for him at the table, he flees upstairs to discover his room completely erased.

In Jack’s room, he reads a poem from Charlotte’s notes urging people to face their fears rather than flee. He realizes Charlotte was never a witch and that President Fear must have broken into her desk to suppress her message. The real Jack then appears, looking frightened and guarded under his Captain America mask. This confirms Charlie’s theory that he is his brother’s nightmare. Talking calmly, Charlie draws out that Jack still remembers some details about their mother, like the fact that she made the Captain America costume and used to sing them a lullaby. Charlie promises to share more memories of her and to be a better brother. Jack admits he loves Charlotte.

As the nightmare lifts, Jack leads Charlie to the tower, where the portal shows Charlotte asleep at her Waking World desk. Jack explains that Charlotte sent Meduso, and that only the two brothers can see the portal. As Jack begins to wake up, he promises to find Charlie if he doesn’t return.

Morning light tints the black walls purple, and Charlie feels for the first time that the mansion is his home. He finds the witch in the kitchen, who is awaiting reassignment after her failed mission. When Charlie argues that retired nightmares become dreams rather than dying, she agrees to consider it. She warns that the portal is still open because his deepest fear is unresolved. Outside, his friends point to his old childhood home and say the figure in the yard looks like his mother.

Charlie finds his mother kneeling over a cluster of mushrooms in the yard of his childhood home. They embrace. She points to the mushrooms and recalls the lesson she once taught him: When the tree died, it brought the mushrooms to life. Charlie begs to stay with her, but she gently refuses.

On the porch steps, Veronica tells him about the history behind the portal. Charlotte’s ancestor Silas DeChant became so consumed by his fear of abandonment that a portal opened in his isolated mansion. His fiancée spent a year tracking him down. Seeing how far she had come to find him proved he would never truly be alone, so the portal closed. The couple founded Cypress Creek, and she painted the mansion purple because she considered it “a happy color.” Veronica also reveals that she and Charlotte were best friends who explored the Netherworld together as children and that Charlie and Jack have rare abilities that make them the portal’s rightful future guardians.

Finally, Veronica tells Charlie he must say goodbye because letting her go will end his nightmare and allow her to become a dream he can visit whenever he needs her. Charlie holds on as long as he can, then says goodbye. She promises to see him in his dreams.

Walking back up the hill to rejoin his friends, Charlie watches his old house shrink and vanish as the territory of his defeated nightmare collapses behind him. For the first time in years, he feels genuinely free.

Alfie asks if the portal is closed now because Charlie’s fear kept it open. Charlie sprints to the tower and finds that the portal is gone. Meduso is there, looking untroubled and studying a portrait of himself that Charlotte drew. He reveals he slipped through the portal to update Charlotte while Charlie said goodbye to his mother and admits that he doesn’t yet know how to reopen it.

Rocco reminds everyone they promised to rescue the students still trapped at the school. Alfie adds that he, Paige, and Rocco still have their own nightmares to face. Charlie agrees that they’ll leave the portal problem to Meduso and save the children.

Nightmare Elementary is now a fortress complete with a foul moat, a razor-wire fence, vicious dogs, and six goblin-manned guard towers. President Fear offers the children a deal: If Alfie can complete the obstacle course, the group may proceed to the school, but if he fails, all four will be imprisoned. Before Charlie can refuse, Alfie accepts, declaring the course is his nightmare and he’s ready to face it.

The goblins laugh as Alfie bellyflops into the moat, but he reaches the far side quickly. When Fear cheats by releasing piranhas, Alfie climbs out, tears two fish from his underwear, and moves on. He drops to his knees and digs a tunnel under the fence, drawing more mockery. The goblins’ laughter stops as Alfie emerges from under the fence and sprints toward the school as the guard dogs trail behind. As Alfie reaches the gate, the entire obstacle course vanishes.

The children inside cheer and call him the “Amazing Turtle.” Alfie explains that his nightmare was never about athletic ability; it was about being laughed at. By letting the goblins underestimate him, he turned their mockery into an advantage. President Fear, furious, declares that the school doors are still sealed and threats still lurk inside.

The children at the windows scatter, and sounds of panic echo through the school. President Fear tells Rocco that passing the test is the only way to free the trapped students. After a fruitless search for alternatives, Rocco sits down at a desk. He asks Fear a pointed series of questions, confirming that every student has a different nightmare and that no creatures have actually been seen inside. Fear shuts the questioning down, and Rocco determines that the students’ own terror is keeping them trapped. Rocco then writes furiously on the multiple-choice sheets, folds every page into a paper airplane, and sails them through the barred windows.

At the bell, Fear grabs Rocco’s remaining test sheet and sees that it has only a large A+ written on it. Rocco points to the far side of the school, where dozens of students are streaming out. His airplanes carried instructions: “THE ONLY MONSTER IS OUTSIDE THE SCHOOL. HIS NAME IS FEAR. DON’T LET HIM BEAT THE KIDS OF CYPRESS CREEK” (329). The instructions also guided the students to use the cafeteria trash chute as an escape route. A small girl tells Charlie that her friend Amber is still locked in a third-floor bathroom. Fear seizes on this, declaring the test a failure if even one student remains. He orders the goblins to recapture everyone. A car horn sounds in the distance.

As goblins begin to recapture the students, Dabney arrives in a small car with Meduso. They’re escorted by hundreds of rebellious nightmares who form a protective circle around them. Dabney publicly accuses Fear of torturing humans in violation of the nightmares’ code. Charlie steps forward to back him up, exposing Fear’s treatment of the school’s children.

Paige volunteers to enter the darkened school to rescue Amber, confronting her own nightmare in the process. Fear straps a camera to her head and projects her progress on the school’s exterior wall. The Dark emerges from a locker and stalks Paige, then multiplies into dozens of figures and drags her toward a door under the stairs. A scream from Amber on the third floor gives Paige the resolve to break free. Using the girl’s voice to navigate, she reaches Amber in a bathroom stall and leads her safely out.

While everyone is watching Paige, Fear’s goblins capture Meduso. Fear destroys his own protective sunglasses in a gesture of defiance, and his goblins do the same. Fear then commands his forces to attack. The Dark intervenes from the school doorway and demands that the children be freed. Fear turns the school lights on to dispel the Dark, but Medusa steps into the doorway and turns Fear to stone. Paige and Amber shove the statue over and shatter it. Medusa banishes the goblins and helps all the freed children return to the Waking World, but Charlie stays behind.

Before leaving, Meduso addresses the assembled nightmares and announces his retirement, crediting Charlie and his friends with showing him what real courage looks like. He gazes into a golden compact mirror, turning himself to stone with a smile, and passes into the Dream Realm. Dabney then leads Charlie to the mansion, where the portal has been reopened by Jack’s fear of his brother never coming home. Charlie steps through and is embraced by his friends and brother on the other side.

Some time after the story’s main events, Charlie and Charlotte work together in the tower room to finish her illustrated book about the Netherworld. Jack joins them to look at her monster drawings. Charlotte confirms Meduso is happily settled in the Dream Realm and warns Jack against trying to reopen the portal himself. A commotion below sends Charlie to the kitchen, where Rufus, a dog freed from petrification following Meduso’s retirement, is chasing Aggie. Charlie separates them, stirs a foul-smelling herbal potion for Charlotte’s herbalist business, and greets his father, who arrives home with pizza. On his way to call everyone for dinner, Charlie pauses at the staircase landing to look at two portraits now hanging side by side that depict Silas DeChant and his mother, the latter painted by Charlotte. He shouts up the stairs for Jack to tell “the stepmonster” dinner is ready.