Castle in the Sky & Theme song

Plot

According to the story's premise, human fascination with the sky prompted increasingly sophisticated ways of lifting aircraft from the ground; ultimately including flying cities and fortresses, of which most were later destroyed during an unspecified catastrophe, forcing the survivors to live on the ground as before. One city, Laputa, remains in the sky, concealed by a violent thunderstorm; whereas large airships remain in common use.
Aboard a civilian airship, a girl named Sheeta is escorted to an unknown destination by sinister-looking agents under Colonel Muska. The ship is attacked by a group of sky pirates led by an old, vivacious woman named Dola and her sons Charles , Louis, and Henri. In the resulting disorder between Colonel Muska's men and Dola's pirates, Sheeta takes a small pendant from Muska and escapes through a window. The sky pirates attempt to seize her and the pendant, but Sheeta falls from the ship, whereupon the pendant radiates a blue light and she gently floats to the ground. An apprentice miner named Pazu witnesses this and catches Sheeta, whom he conveys to his own house. There, she finds a photograph of Laputa, which Pazu's deceased father, an airship pilot and adventurer, had taken but was disbelieved by his contemporaries. Pazu believes the city exists and wishes to find it.

Dola's sky pirates arrive at Pazu's house, forcing the children to leave, with Sheeta in disguise. They are pursued by Dola's pirates and cornered by soldiers; but fall from a collapsing rail trestle and are saved when Sheeta's pendant activates once again, allowing them to float safely into an abandoned mine shaft.

Inside the mines they meet an old miner, Uncle Pom, who tells them of "volucite" (levistone in some subtitled versions, levitation stone in the original English language dub, and aetherium in Disney's English language dub), the crystal that keeps Laputa aloft. He reveals that Sheeta's pendant is one of the largest and purest of such crystals in existence and counsels Sheeta to remember that the crystal's power rightly belongs to the earth and that she should never use it to commit acts of violence.

Upon returning to the surface of the land, Sheeta tells Pazu that she has inherited an ancient "secret name": Lusheeta Toel Ul Laputa (Laputian for "Sheeta, True Ruler of Laputa"). A plane then unexpectedly lands with army soldiers and the two are captured, placed in a fortress, and separated.

The general in command of the fortress discusses with Muska the government-sponsored search for Laputa and agree that Sheeta and her crystal are the keys to its discovery. Muska reveals to Sheeta his knowledge of her true name, shows her a huge android robot believed to have been created in Laputa, and tells her that unless she cooperates with him in the search of Laputa and unlocking the crystal's secrets, which he believes can be used to physically locate Laputa, Pazu is likely to come to harm. Seeking to protect her friend, Sheeta tells Pazu that she has agreed to cooperate with Muska and the army in search of Laputa and asks him to forget her and Laputa. Stunned by this apparent rejection, Pazu returns to his village only to find Dola's pirate family occupying his home and eating dinner as they capture him upon arrival. Pazu tells Dola of his experiences. When the pirates learn that Sheeta, Muska, and the general will depart the fortress in search of Laputa aboard the gigantic military airship Goliath, Pazu begs Dola to take him with her.
In the fortress tower, Sheeta absent-mindedly recites a spell given by her grandmother, causing the crystal to illuminate a strange blue light that points to Laputa. The spell also re-animates the robot, which wreaks havoc all over the fortress, setting it on fire. The robot rescues Sheeta, demonstrating its loyalty, before it is destroyed by the Goliath airship. In the meantime, Dola and Pazu show up and rescue Sheeta from the burning tower, but her crystal is torn from her neck and later recovered by Muska, who uses it to track down Laputa. The children and Dola's pirates pursue the Goliath aboard the pirate ship Tiger Moth, intent on finding Laputa before the Goliath does. That night, as Sheeta and Pazu stand watch on the crows nest, they talk at length about their respective lives, touching upon Sheeta's study of magic words and mentioning one such spell, the Spell of Destruction, a power Sheeta has never used. Dola, who is awake in bed, overhears their discussions through the intercom.
Amid their conversation, Pazu sees the Goliath rise from the clouds. The airship attacks, but the Tiger Moth escapes unharmed. The Tiger Moth enters a storm, and Dola tells the children to keep watch above the clouds by turning the crows nest into a glider. Soon a massive cloud becomes visible, which Pazu recognizes from his father's descriptions as Laputa's hiding place. As they try to find a way in, the Goliath attacks again and the glider Sheeta and Pazu are riding is blasted away from the pirate ship. After a harrowing ride through the storm-charged cloud, the children land in Laputa, only to find the city devoid of human life, having only a single robot among the ruins taking care of the grounds and its plant and animal life. In the grounds is a gargantuan tree, whose roots have pervaded Laputa's base.

The Goliath arrives at Laputa, whereupon the soldiers plunder the city's vast treasures. The Tiger Moth is found wrecked on the surface, with Dola and the pirates being held captive. As Pazu attempts to rescue Dola, Sheeta witnesses Muska locating a hidden entrance to a large sphere that surrounds the city's core; she is subsequently captured and taken inside. Pazu frees the pirates and, after many difficulties, finds another way into the sphere.

Muska takes Sheeta into Laputa's core, a chamber holding a gigantic Volucite/Aetherium crystal that serves as the city's power source, and reveals that he is also an heir to the throne of Laputa. He takes control of Laputa and all its technology and demonstrates the power of the city to the army by beaming an immensely powerful blast toward the surface. Betraying the general and the army, he then activates hundreds of robots to wipe out the army and the Goliath while Dola and the pirates hide from the robots inside the remains of the Tiger Moth. Sheeta frees herself, steals back the crystal and runs through the core with Muska in close pursuit. Eventually, she finds Pazu and passes the crystal to him.
Muska finally corners Sheeta in the city's throne room. He brandishes a handgun at her, blasting off her braids. Pazu, with a hand cannon provided by Dola, then enters and asks for a moment to talk to Sheeta, which Muska grants. Together, the two children decide to use the Spell of Destruction; with a single word, the pendant releases an enormous power surge that triggers the collapse of the city's core. Muska is blinded by the flash and falls to his death, while Sheeta and Pazu are hurled into the tangle of roots from the giant tree and survive. Afterwards they find their way back to the glider, also lodged in the tangle of roots, and leave Laputa.

The Dola pirates also survive Laputa's destruction aboard their moth fighters, and are overjoyed to be reunited with Sheeta and Pazu in midair, with some Laputan treasure as a compensation for their troubles. After reaching the coast, the pirates and the children bid each other a fond farewell and part ways. The ending credits show the remains of Laputa, held together by the tree, continuing to rise, until they apparently establish an orbit high above the earth.