Big Fish & Begonia (大鱼海棠, Dai Hai) is an animated film by B&T.
This is a mythic land where no outsider has ever set foot. The spirit-like dwellers there, however, know us mortals well. They are responsible for human emotions and desires, for seasons, weather, the elapsing of time...
Our protagonist, a spirit girl named Chun, has just turned sixteen and goes in the form of a dolphin to explore the earthly part of the sea, to see what the human world is like. While cruising at sea, Chun gets caught in a storm and finds herself enmeshed in a fishing net. A human boy spots her and comes to her rescue, trying to free Chun from the entanglement. By accident, the boy drowns leaving Chun wretched and heartbroken.