Working at Winged Mail is prestigious if you live in the post-apocalyptic state of Anfix. The world is now ruled by steam technology, balloons fly across the sky, and mechanoids take care of pets, because all animals became extinct as a result of a catastrophe decades ago.

Gabriella, a postal pilot, and her friends receive the task of delivering a registered letter. personally at the coordinates pointing to the very wilderness. It would seem like a harmless order. But this is just the beginning, and in its execution the heroes will have to face each other's past and face an uncertain future.