A pair of siblings riding a bull-headed horse arrive at the seaside. Elephant-headed younger sister Oscar tries to dissuade horse-headed older brother Alex from going into the water to swim. However, Alex pays no heed to his sister's words and dives headfirst into the sea, swimming alone. A massive wave overturns him in the water, and Alex struggles before sinking beneath the surface. Oscar, who had been secretly angry, grows worried when her brother fails to return after a long time. The bull-headed horse comforts her, and the two decide to go search for Alex. In the underwater world, they encounter a black giant whale. Oscar approaches to inquire but receives no answer. The two climb onto the whale's back, enter through its blowhole, and arrive in a magical world. They see a dolphin trapped in the sand and also discover Alex. However, the bull-headed horse becomes stuck in the rocks and loses an arm. He urges Oscar to leave quickly, and the heartbroken Oscar eventually departs. Returning to the real world, the siblings float lonely on the sea surface as the sun sets. 　　This unconventional surrealist animated short film constructs a disquieting and bizarre world through its distinctive art style.