There is a baby elephant whose name is Aeko. His name means "a lovely elephant" and he has heart-shaped ears. Not like other elephants, Aeko has special abilities that he can run with soft steps and fly up into the sky. Furthermore, he is a magician who can blow hearts out from his nose. Aeko has three lovely friends. They are the chatty bat Jjabak who is not afraid of night, the strong naughty bear Yagom and always cheerful and reliable whale Bongo. These four good friends always have a fun time together. One day, Aeko and the lovely friends enter the "Numberland" by a chance. There, Aeko meets new friends who have the number-shaped ears and horns on themselves and has lovely time together. Sometimes they meet diverse problems but go through the difficulty with their friendship and love. In this process, they realize concept of mathematics.