Pazu, a young engineer, rescues a girl that floats down from the sky with a mysterious glowing pendant. A great adventure ensues as the boy and his new friend, Sheeta, embark on a quest to find the legendary Laputa, the Castle in the Sky, and the secret of the girl's necklace. On the way, they join up with a band of rambunctious, friendly pirates in their attempt to escape the greedy army and the secret service, led by the evil Musca.