The mysterious song of humpback whales fascinates researchers worldwide. But why do the whales sing? Underwater camerawoman Christina Karliczek Skoglund dives into the world of these powerful-voiced marine mammals with marine biologist and cameraman Florian Graner. They encounter curious calves, spectacular battles, and a young whale playing with dolphins. On her journey, Christina also meets scientists. Are we on the verge of finally cracking the "code of the whales"? And how can AI help us?