The earthly world is a world of love, warmth, goodness, where all actions are performed at the behest of the heart. The underwater world is a world of loneliness, coldness in relationships and feelings. These two worlds were connected by friendship. The little princess had to go through a lot to find true friendship, which she then had to sacrifice to save her friends. And you know, true friendship never goes away, it lives in your heart as long as you live. It is not affected by distance, weather, or time, and only true friends will find the opportunity to convey a message with their love.