As the owner of the lion's birth mark and a prince, it was Robin's job to protect the Earth from evil. He knew his mother was cursed, but he yearned for a little sister. His desire was fulfilled. The little princess was born as the second heir to the lion's birth mark. Robin was overjoyed. But this joy didn't last for long. Tragedy was awaiting both of them. A tragedy that would change their lives forever. What will happen and how will it all end?