A year after her disappearance, Adrien discovers a clue hidden away in his father's office that hints at what really happened to his mother . With the help of Marinette and his friends, he begins a journey to unearth the truth and figure out just how his father is involved. However, the truth isn't always what you expect and his discovery is just the tip of the iceberg. Revelations along the way lead them down a path that uncovers something much bigger, threatening their lives and leaving the future of Paris hanging in the balance.