The King of Angels have recruited some of Heaven's people to be guardian angels. One of them is Lee Taemin. "So, Lee Taemin, You're just recruited as a guardian angel. Who do you want to guard? Pick one human in the earth. Just one. And I'll transfer you to the earth." said the King of Angels. "Can you pick me one, your highness? There's a lot of beautiful girls but I can't find who's comfort for me.." That little boy is seeing down to the earth and seem confused. "How about her?" The King of Angels pointed to a young calm beautiful Korean girl who is walking at the pedestrian street. "That's a good idea, your highness! Who's her?" "She's Kang Yungra. Guard her, I guaranteed she suit you the most." "Okay then. I want to protect her." "Say the Guard Swear now." "I promise to guard Kang Yungra, she'll be my part of life and I must survive for her." "Great. Goodbye, I'll see you soon. If you're failed, you can go back to the Guardian Military soon." "Sure, your highness. Thanks for everything. I promise I'll protect her. And I will miss everyone here.." "Go now, taemin! Be a nice guy in earth." The spiral of transision is running. Taemin went in to that spiral....