A young girl and her brother venture out too far into the deep ocean. Suddenly, a giant eel, the Great Puhi, grabs her brother and pulls him under. Frantic, Nani, his sister, turns to the sea creatures for help. But every animal she asks shakes their head no and says they cannot help. Losing all hope, Nani then discovers that it's the smallest of all the sea creatures who, without hesitation, comes to the rescue.