Kujira no Kora wa Sajou ni Utau

An island called the Mud Whale is located in a world with an infinite sea of sand. An old village with most of its residents being "Marked," a trait with a double-edged sword that gives people magical talents but also makes them more likely to die young, is located in its interior. Chakuro, a young and inquisitive village archivist, spends his time recording the discovery of new islands. However, each one is similar to the others in that it has been abandoned save for the remains of previous residents. Chakuro and his buddies decide to join the scouting party when another island appears on the horizon for the first time in the previous six months. They discover remnants of an ancient civilization while on the journey. And Chakuro finds a girl inside one of its crumbling ruins who will alter both his destiny and the Mud Whale as he knows it.