1786. Thirteen year-old Alma and her brothers Lam and Soum live in a hidden African valley, protected from the savagery of the outside world. One day, Lam leaves, lured by the desire to find out what lies beyond the valley. Alma sets out to look for him. Meanwhile, at a port in Lisbon, Joseph Mars stows away aboard a slave ship, La Douce Amélie. The young French orphan is on the hunt for treasure. On the turbulent Atlantic crossing between Africa, Europe, and the Caribbean, the fates of the two children will become irreversibly intertwined.