From Aerandria Scans:

During the age of romanticism in Japan, the capital was leveled to the ground by a powerful earthquake. One of the many orphans it left was Sorato, who was taken in by Baron Kamichika. In his new home, the “Blood Blossom” Estate, Sorato meets the baron’s heir, Garan, and his fiancee, Kiyora, and the three swear their eternal friendship. But that promise is soon showered in blood because of secrets and desires nobody could have ever imagined to exist…