In the radiant summer elegance of Cabourg, young Albertine lives peacefully with her widowed father inside the magnificent Grand Hotel. Beloved by the hotel staff and enchanted by the endless sea, her life changes forever when she meets Sidney, a refined young visitor whose quiet charm awakens love in her heart. Watching them from afar is Marcel, a writer fascinated by memory and emotion, who begins to transform Albertine into a character for his future novel.

But the romance of the season turns into danger when the Grand Ball of Cabourg ends in murder. The powerful Duke of Callen is found dead inside a private salon, and Albertine becomes the only witness to a clue that can reveal the killer’s identity. As fear spreads through the hotel, she finds herself hunted by the mysterious Count Beaumont. Between moonlit beaches, hidden letters, and deadly secrets, Albertine and Sidney must survive a conspiracy before the summer .