Hitsugi no Chaika EP10 - Fortress in the Sky

Arriving at Iveco, Toru realizes that something is strange about town: there are no young girls. There is also a uprising lack of magic fuel given that this region is famous for its mines of magic fuel. They learn from a shopkeeper that Duke Gavarni has been using all of the town's magic fuel to power the floating fortress Soara and that his soldiers are kidnapping the town's girls and taking them to his fortress where they are never seen again.