"Originally published in 2014 in French by Rue de Sèvres as Le château des étoiles - 1869: La conquête de l'espace - volume I" -- title page verso.
Summary
A year after his mother disappeared in her hot air balloon, Seraphin and his father receive a clue that sends them to a Bavarian castle where lurks a force that would stop at nothing to conquer the stars.