A Loser's Redemption

Kang-min didn't have a life, he was bullied constantly in school, his family in shambles as they were constantly scratching on the poverty line. Even at the age of 32, he didn't get a break, his wife was cheating on him, his mother and father passed away, his sister suffered from a rare form of cancer.

In a great grief, Kang committed sucide ,however, he awoke 20 years in the past. What's going on??