Gwangyeui Ouroboros

The vicious cycle of the ouroboros.
Life at school is bleak for outcast Hyeon. But one day, she receives a letter from Jeong, her dear old friend from middle school. Filled with nostalgia and excitement, Hyeon begins reading the letter... only to discover that their time together was a nightmare for Jeong. Where did it all go wrong?
(Source: Manta, edited)