Nigai Kajitsu
A Bitter Fruit
苦い果実
1) A bitter fruit (Nigai Kajitsu)
The first story is of a man who was locked out of his apartment while his wife was together with another man. He fainted as he was sick, and his neighbour who passed by, took him home...
2-3) Dark Passion
A high school student is submitting to sex with a yakuza in order to repay his father's debts. The father was keeping drugs for the yakuza but ended up using them and became addicted. The only bright light in the student's life is his lover, but one day he makes a horrible discovery.
4) BLUE PERIOD
The last story is the prequel to the first story in "Last Kiss Kara Hajimeyou {Let's begin with our LAST KISS.}". A mixed japanese-black student in a school is attracted to a chinese, who looks like the japanese cousin he likes. He heard rumours that the chinese boy caused a male teacher to quit cos they were caught together... (Source: MangaUpdates)