In an accident, a young dolphin strayed into a crab trap, causing serious injuries to its tail fin. Fortunately, it was found by a little boy and taken to Clearwater Marine Hospital, where it had a new name - Winter. A new life unfolded before Winter. For mammals living in the ocean, the tail fin is so important. Only with the tail fin can they have the ability to swim, dive and float in the sea water, and breathe fresh air. Winter, whose tail fin was damaged, would die of suffocation unless he floated on the sea for his whole life. In order to save Winter, a group of highly skilled scientists gathered together and used their ingenuity to invent an artificial tail fin. Winter, who was equipped with an artificial tail fin, became the embodiment of courage and hope.