Ten-year-old Chihiro Ogino is moving with her parents to a new town when they become lost and find what appears to be an abandoned amusement park. Chihiro’s father decides to explore it while a reluctant Chihiro and her mother accompany him. They soon discover a stall with food, and Chihiro’s parents sample the food, but find themselves unable to stop eating. Chihiro soon realizes that she is in a magical world when she sees her parents literally turn into pigs.
Running to get help, Chihiro finds a boy, Haku, who smuggles her into a large bathhouse and tells her to find a job so she can stay there until he can help her recover her parents and escape. Haku also hints that he knew Chihiro when she was little. Haku instructs Chihiro to see Kamaji at the boiler room to ask for work. Kamaji, a six-armed, grumpy, but kind-hearted fellow, says he has no work for Chihiro and entrusts her to Lin to take her to Yubaba. Yubaba, the cranky, elderly witch who runs the bathhouse, agrees to let Chihiro work for her, but takes all of Chihiro’s name except the first character of her first name, which Yubaba calls “Sen.” Sen later learns that Yubaba controls her servants by taking their names.
While working, she sees a masked spirit, named “No Face,” outside of the bathhouse. She leaves the door open and he enters the bathhouse. Sen’s first customer is a heavily polluted river spirit that all of the other workers avoid. When Sen successfully cleans the spirit, it rewards her with a dumpling-like object. Afterward, Sen discovers that Haku is actually a dragon, and when he is attacked in this form by shikigami in the form of paper birds, leaving him seriously wounded, she feels him the dumpling. Haku coughs up a gold seal and an odd black slug, which Sen squishes. When Haku remains unresponsive, Kamaji tells Sen to visit Zeniba, Yubaba’s identical twin sister, who owns the seal, so the curse of the seal can be lifted. Kamaji gives Sen train tickets for her to be able to travel to Zeniba’s swamp. She is accompanied by Boh, Yubaba’s giant baby son, whom Zeniba had turned into a mouse.
During this time, No Face swallows a spirit in order to use his voice and makes fake gold nuggets to order food and other items from
the staff. No Face becomes larger as he eats, and swallows several spirits after Sen declines his offer of gold. Later, Sen lures him out of the bath house by feeding him the remainder of the dumpling, which causes him to vomit until his stomach is empty and he is back to his normal self. No Face accompanies Sen and Boh/mouse to Zeniba’s house on the train.
Sen visits Zeniba, who she finds is very friendly and pleasant, in sharp contrast to Yubaba. Zeniba says that Sen had broken the seal’s spell by her love and caring and that the slug that Sen killed was a curse that Yubaba had placed on Haku to make him her slave. Haku, now fully recovered, comes to pick up Sen. No Face remains with Zeniba. On the way back, Haku says that if they return Boh, Yubaba’s son, to Yubaba, she will free Sen and her parents. Sen returns the favor by helping Haku remember his full name by reminiscing as a child when she fell into her hometown’s river and was saved by the current (Haku in his river dragon form). The river’s name was the Kohaku River, and Haku’s real name was Kohaku. At the remembrance of his name, Haku is completely freed of Yubaba’s spell.
At the bathhouse, Sen returns Boh to Yubaba, but the witch has one final test: Sen has to identify which of a group of pigs are her parents. Sen looks closely, then says that there must be a mistake; her parents aren’t there. This breaks the spell on the pigs and forces Yubaba to give Sen the rest of her name back and let her go. Now “Chihiro” again, Haku leads her to the entrance of the spirit world, saying that her parents are on the other side but warns her not to look back (he did not explicitly state a reason for this), though they promise to see each other again. Chihiro meets her parents, and they continue on to their new home.