Hocus Pocus begins in a small town in 1693, were a teenager named Thackery Binx realises his little sister, Emily, has fled into the woods, under the control of a witch. Thackery urges his friend Elijah to hurry back to the village and alert the elders. He then rushes after Emily, and eventually finds a pilgrim-style mill house where Emily has been captured. Inside the house, three aging evil witches known as the Sanderson sisters-- Winifred, Mary, and Sarah (Midler, Najimy and Parker)-- are brewing a potion in a cauldron. Winifred, the eldest sister, highlights that the potion, when drank by a child, has the ability to rejuvenate them and restore their youth. Before the witches can force the potion into Emily, Thackery stops them and engages in a brawl with Winnie, and is soon stripped of his energy. The sisters then suck the life-force from little Emily and their youth is restored, then cast a spell on helpless Thackery that he take the form of a black cat for eternity. Immediately after, the angry villagers, wielding torches, capture the sisters and prepare to hang the trio from a branch of a tree. Thackery's father demands that Winifred divulge his son's whereabouts, but she refuses to say. Winnie's spellbook reveals a prophecy that on All Hallows Eve, a virgin shall light the black flame candle and resurrect them. The sisters are then hanged and Thackery remains a feline, unable to reassure his parents that he is okay. He rubs against his father's leg, but the father, not recognizing him, pushes him away, thinking a black cat to be a bad omen..
300 years later, in Salem, a teacher tutors her class about the Sanderson sisters, since Halloween is approaching. Max Dennison, a new student after arriving from Los Angeles, isn't gullible towards the tale and befriends fellow classmate Alison as the school closes for Halloween break. While cycling home, Max cuts through a cemetery and runs into two rebellious teens named Ice and Jay who tease him, later stealing his trainers. When an irritated Max returns home, unhappy about his new location, he finds solace in his room and daydreams about Alison. Dani then frightens him and demands that he take her trick or treating later into the night, at first he refuses, but is later forced to take his little sister into the neighbourhood to collect candy. After an embarrassing confrontation with Ice and Jay, Dani storms off on Max and he goes to reconcile with her. The two then find a mansion run by Alison's family and they engage in a conversation about the Sanderson sisters, planning to break into the abandoned museum dedicated to them. Dani is anxious about their Halloween prank, and when they break into the mill house, now a museum, Max foolishly lights the black flame candle after Dani tries to dissuade him from doing so. Odd occurances begin to haunt the Sanderson house and the floorboards rattle, presenting the Sanderson sisters returning back home. The three kids hide while the sisters comicly settle back into domesticity after a centuries-long stay in hell. Dani soon shows her face, claiming that she was the one who lit the candle. To protect his sister, Max and Alison distract them and engage in a brawl. Max fools the Sandersons by setting off the modern sprinkler system, making them think it is a terrible magic that will destroy them, in order to distract the witches from following him. He then steals the spellbook and is introduced to Thackery, a now 300-year-old feline with the ability to speak. After escaping the Sanderson sisters, Max, Alison and Dani follow Thackery 'Binx' into a cemetery where he shows them Billy Butcherson's grave and his sister's headstone, they soon realise he is Thackery Binx, and that the legends are true.
The sisters discover they have been tricked and devise a plan, since the candle only brings them back for one Halloween night, they plot to suck the lives out of children before sunrise, so that they can stay alive and youthful forever, but need to find Max since he has stolen the book. The witches set out into a more modern world, and are constantly confused as to the ways of the world in the early 90's. They track down Max and the gang to the cemetery, unable to set foot on hallowed ground, and taking flight on their broomsticks (Mary's broomstick is actually a vacuum cleaner). Winnie resurrects Billy Butcherson, now a decaying zombie, to find the trio after losing them. The kids take rescue in a sewer and make their way through the underground while the witches board a bus and seduce the driver. Binx finds a sewer hole that they can escape from Billy and makes his way out into the streets, and is then run over by the bus the sisters have boarded. Binx returns to normal health, since he is immortal, and the witches depart the bus in Halloween-themed suburbia. Max, Alison, Dani and Binx soon enter city hall, crowded with people attending the Halloween party so that they can find their parents. The witches encounter an elderly man in a devil-costume and believe he is really Satan himself, and soon learn what All Hallows Eve has become in modern times.
When the witches enter city hall to find the children, Max's parents do not believe them and he is forced to tell the party-attendants on stage that the witches have come back to life. Everyone laughs until Max points at the Sandersons. The spotlight soon switches to Winnie and her sisters, and everyone stares. But Winifred quickly turns the tables on Max, wow'ing and dazzling the partygoers with a fabulous song and dance number (as only the Divine 'Miss M' can). The song contains an insidious spell by which the Sandersons compel the partygoers to all dance and party until they die of exhaustion.
Max and the gang flee the city hall party, and hide from the sisters behind a restaurant alley. Alison soon has an idea and they go to their high school. The witches enter the school, since Mary has caught the scent of children. Thinking it is a prison for children, the witches search the halls and follow a voice, actually played by tape recorder and step into a furnace, Alison and Dani then close the hatch and turn the heat full blast, defeating the witches forever. In celebration, Max and Dani head home with Alison, deciding to raise Binx as their own cat. They fall asleep, certain that the witches are gone forever. But Winnie, Mary and Sarah soon emerge from the furnace and take their normal form after being burnt alive, but are desperate since the children have the book and they can't remember the spell for eternal youth. Along the way, returning home, the witches run into Ice and Jay and hold them hostage in cages at their home. Winnie breaks down, certain that they are doomed. At the Dennison household, Alison and Max wake up, both feeling sympathy for Binx in his feline-form. They open the spellbook to see if they can reverse his spell, and the book emits a signal that Max, Alison and Dani cannot see, but the Sanderson sisters see the signal from across town. Winnie soon takes flight along with Mary and Sarah and they head into the suburbs on broomsticks to retrieve the book. Max and Alison try to reverse the hex on Binx, but he stops them, angrily warning them that the book can only be used for ill, never for good.
Alison has an eerie feeling that something isn't right. Acting on her uncertainty, she and Max fetch some salt from the kitchen, as a defence mechanism if the witches do return. Max and Alison's moment of romance is interrupted by odd noises from upstairs, and they go to see what happened. Alison learns the book is gone, and pulls back the covers of Dani's bed to reveal Sarah. Mary and Winifred enter from the closet holding Dani hostage and having retrieved the book. To defend herself, Alison pours salt round the room and the trio of witches take to the skies with Dani. As Max and Alison are in need of a miracle to get Dani back, Sarah sings a gentle spell from the skies to summon all the children of Salem to the Sanderson house. Sarah returns home, and Winnie is fixing up the potion in their cauldron while Dani is tied to a chair.
Max enters the Sanderson house in time to save Dani from consuming the potion, and the sun begins to rise. The sisters fall to floor, but are tricked for a third time as the ray of light turns out to be the frontal beam of Max's car. The sisters have the opportunity to suck the lives of the children that are approaching their house, but Winnie is determined to have Dani's soul since she called her 'ugly'. However, there is just enough of the potion left for one child, so they take flight on their broomsticks. After losing the witches, Max, Alison, Dani and Binx return to the cemetery since the witches can't set foot on hallowed ground. Dani protected by a ring of salt as Billy, the zombie, joins them since he also has a hatred for Winnie. The sisters find them in the cemetery and swoop at them from all angles. Winnie knocks Billy's head off, and Dani carelessly leaves the safety of the salt ring to retrieve it and give it back to him. Winnie captures Dani and is about to force her to drink the potion when Binx rushes up a tree and leaps, knocking the potion from her hand, Max catches the potion and threatens to smash it unless Winnie releases his sister. But Winnie threatens instead to kill Dani if Max does this. The standoff is resolved when Max suddenly drinks the potion, forcing Winnie to take him instead. Winifred frees Dani, claiming that Max is a fool to give up his life for Dani. Winnie then attempts to suck the life out of Max, as Alison and Billy prevent Mary from helping Winnie. Alison, Dani and Billy catch hold of the extension cord dangling from the vacuum cleaner Mary is using as a broomstick, Sarah tries to help Mary, and a tug-of-war ensues, ending when Alison, Dani and Billy release the cord, causing Mary and Sarah to fly off helplessly into the sky. Winnie is knocked off her broom while struggling with Max, and lands on the cemetery's hallowed ground, taking hold of him and sucking his life-force. The sun begins to rise from the horizon of the cemetery, Winnie is then fixated between the sun and the hallowed ground, slowly turning to stone. The Sanderson sisters then disintigrate from the sunrise and Binx takes his final breath, the curse on him broken. Dani and Max are reunited, and she is touched that he would give up his own life for her. Dani then realises that Binx is dead and begins to weep over him. But suddenly Thackery's spirit appears to console her, showing her that the curse is lifted and he is free. He thanks her, and Max and Alison, for their heroic fight against the Sanderson sisters. Emily's spirit suddenly appears and Thackery is finally reunited with his sister. The film ends with Max, Dani and Alison victorious after the defeat of the Sanderson sisters, and Dani smiling as Thackery and Emily finally cross over through the cemetery gates into heaven.
Premise: After the end credits, Max and Dani's parents exit city hall with the other partygoers, exhausted from hours of dancing, then cuts to Ice and Jay still hanging from the cages at the Sanderson home, singing 'Row row row your boat'. As the credits approach, the spellbook opens its eye.