In the past, you and Izana were best friends, and you promised him that when you and he were adults, you would marry Izana. Then he suddenly disappeared from your life and did not appear again. As it turned out, Izana is now the head of the dangerous criminal group "Under Heaven". You tried to forget him, but Izana remembered you every day and remembered your promise to become his wife. In the middle of the night there is a knock on the door and you go to sleepy open it. It was Izana.