Jimin comes back to his highschool, after a month's detention. He goes back to his normal life...... Which was of a bully until a mysterious trail of letters leads Jimin on a magical scavenger hunt through the hidden world that exists right in his highschool which he had never discovered before. The mail trail is work of an anonymous gaurdian angel, who changes his life completely. But who is this person? And why did she chose him? With each letter, secrets are revealed and bonds are formed - as Jimin learns about friendship, care and finding the good in people in this cruel world.