Yaoi - Boss and employee

Shinwoo met the populat Han in high school but drifter appart just before garduation. It has been 10 years since they spoken to one another. Shinwoo proceeded with his life that just kept on going shitter by the year while Han enjoyed his life that bores him. After 5 years Han decided to come back to Korea and start his own bussiness but he was suprised to learn that all his memories of Shinwoo were gone. What is this feeling he feels just by hearing his name and why has he forgotten only him.