The day after Bastille Day, the body of a young Youtuber specializing in videos on history is found on the first floor of the Eiffel Tower... How could the killer have acted without being seen in the middle of fireworks when the eyes of the whole of France were focused on the Eiffel Tower? Captain Laura Giordano, still scarred by the death of her former partner, wants to investigate alone at all costs, but is forced to team up with a newcomer to Paris, Mathieu Bellanger. Behind the scenes, the unstable duo will gradually uncover the unsuspected history of the Eiffel Tower during the Second World War.