Castle in the Sky

This starts off with sky pirates (as in Porco Rosso) planning to attack another airship. They are after a young girl on the airship who is wearing some kind of special crystal.

The floating island

The girl (Sheeta) keeps falling, apparently unconscious, and then the crystal activates. The crystal allows her to float down where she's eventually caught by a young boy. The boy (Pazu) works in some type of mine.

Pazu explains to Sheeta that Laputa is supposed to be a mythical island in the sky but that his father had seen it and took one photograph.

The pirates land and are looking for Sheeta. they find her, but some of the villagers protect her. Someone else seems to be chasing her also. There is a long chase by the pirates and Sheeta and Pazu fall from a collapsing railway but the crystal again activates.

Sheeta explains that her parents had died and she was living by herself when she was kidnapped by the second group now chasing her.

They have fallen into some ancient mines but there they meet Pazu's uncle who says something about the rocks being astir. When he turns out the light, the rocks seem to emit their own light. He explains that the material Sheeta's crystal is made out of is Volucite, the same material that glows when exposed to the air.

Sheeta reveals that her family has an ancient mysterious name and it includes the word Laputa. They end up being captured by the original set of kidnappers backed by the local army.

There are captured and taken to a military base where the commander reveals that they are involved in a search for Laputa. One of the kidnappers shows Sheeta a mechanical soldier that has the same emblem on it that her crystal has. He tries to convince her that Laputa is an enemy.

Apparently Sheeta is the heir to the throne of Laputa. She finds this out when she's interrogated by one of her kidnappers. Pazu is told to leave but, when he returns, he's captured by the pirates.

The battle-cruiser that is scheduled to pick up Sheeta gets closer while the pirates decide to launch their own attack to get the girl. Sheeta remembers an ancient spell she was taught and says it, triggering a rather wild reaction.

Everything goes wild when the captured, supposedly broken, robot comes alive again with the activation of the stone. It escapes from its cell and easily defeats the army fighting it. It is temporarily damaged but comes alive again and attacks, much like Gort in the movie Forbidden Planet. Sheeta is rescued but not before she loses the crystal and it falls into the hands of the kidnappers. Pazu and Sheeta decide to join the pirate group to find Laputa. It will be a mismatch, though, as the pirate ship is small, relatively primitive and lightly armed; the ship they are pursuing is the battle-cruiser which is huge and incredibly heavily armed.

The pirate ship finds a huge cloud that might contain Laputa, but they're attacked by the battle-cruiser, and Pazu and Sheeta, who are in a glider doing observation, get separated from the pirate ship. They crash-land on Laputa.

The floating island seems to be devoid of people, however. They find a giant-sized gravestone tended by what appears to be the one remaining functional robot. The army lands and begins its destruction of Laputa, looting everything they can.

The leader of the kidnappers apparently wants Laputa for himself. He recaptures Sheeta and his men shoot Pazu, but only graze him. Pazu escapes and sets the pirates free. It turns out the really nasty man is also a member of the Laputa royalty.

He wants to use Laputa's weapons systems and demonstrates by setting off a massive explosion. Sheeta manages to grab the crystal away but not before the man manages to kill hundreds of soldiers and destroy their battle-cruiser.

The would-be king threatens Sheeta.

Together Sheeta and Pazu activate a self-destruct spell for Laputa. They manage to escape and Laputa, what is left of it, rises in the sky out of reach of anyone else.