Final Fantasy XII
In the dungeons, Vaan, Balthier and Fran, find Basch. The Captain deemed a traitor by the people. They free Basch from the cage he is being held in and they go away from the Nalbina Dungeons to the Barheim Passage far below.  There in the Barheim Passage, they fight creatures that can imitate treasure chests called Mimics, and they battle a Mimic Queen.  After, the wall collapses, and Balthier, Vaan, Fran and Basch go back into the city of Rabanastre, which is the capital of Dalmasca.  There, they learn that Vaan's friend Penelo was kidnapped by a head-hunter who was looking for Balthier.  The kidnapper is named Ba'Gamnan, and he has taken Penelo to Bhujerba, a city in the sky.  Balthier lets Vaan use his airship, which is like an airplane except different in shape, and they fly to Bhujerba to rescue Penelo