A small key unlocks a great adventure.

When 9-year-old Lucie arrives at Bectoile for her summer holiday, she has no idea of the adventures ahead. Her mother, Caroline, is leading an archaeological dig in the region with her colleague Pierrot. Bectoile is also the town where Caroline grew up, and the scene of a family secret... which Lucie is about to unveil! With the help of her new friend Yann and a very special pair of songbirds, Lucie is determined to delve into her family story. From the depths of a ruined castle to a camper van parked on the edge of the woods, this adventure will lead them from unusual surprises to fabulous discoveries!