Kei (Leo Koo) has just wrapped up a big contract for his company (though it's never clear what kind of work he does). He decides to take a well deserved vacation, to go and visit his girlfriend June (Anita Chan) in Japan. He hasn't seen her in a while.
Kuroi Misa, a girl with Satanic powers, mysteriously appears in various high schools. Carrying a dagger and a heavy leather bag, she uses her powers to eliminate the evil forces that thrive on deadly sins of the human race. Her ultimate aim is to cleanse the earth and rebuild her broken family.
Souta and Doumoto have finally moved together. However, the couple's happiness is short-lived since Souta's older sister, Kozue, unexpectedly goes to her brother for asylum after arguing with their parents and running away from home. Souta will end up developing jealousy towards her sister since he believes Doumoto is interested in her.
