Up until now, Kobayashi Teppei has been living a normal life with his parents. When they suddenly pass away, Teppei is taken in by his grandfather, Arima Ishin. As it turns out, Ishin heads a powerful conglomerate and Teppei is suddenly thrust into high society when he is publicly pronounced to be Ishin's heir. Thus, Teppei enrolls into a prestigious school for the heirs of the rich and powerful, and he meets with four girls who will profoundly affect his life. However, one other purpose drives Teppei on: To discover the identities of the persons responsible for the death of his parents and exact vengeance.