Hanna and Leon are spending their vacation with their Aunt Birgit on an island. The children can hardly wait to finally see their favorite animals: dolphins. Together with their aunt, they take a trip on a boat belonging to a friend of the captain. During the outing, the children even discover a baby dolphin playing joyfully. But suddenly, the little dolphin disappears! Captain Isidoro dives after the animal, which has become entangled in a fishing net. He is able to free it and brings it onto the boat. The children get to help keep the little dolphin moist. Together with Aunt Birgit and the captain, they take it to an animal rescue station, where a veterinarian tends to the dolphin. Since the baby dolphin is only lightly injured, the rescuers release it back into the care of its mother in the open sea. A few days later, the little dolphin and its...