The game is split into three phases: Yin, Yang, and Kuon. The Yin phase revolves around a girl named Utsuki and her sister who travel to a manor in search of thier once renowned, now renegade exorcist father Doman. The Yang phase centers on one of the rare female exorcists, Sakuya who was one of Doman's disciples. She and her apprentices are sent to the manor to investigate the strange occurrences there. After completing both the Yin and Yang phases players can access the Kuon phase which involves a master exorcist named Abe no Seimei.
From the Kuon website:
The tune of Japanese taiko drums and the dark aria of children are heard every night. Residents wander like ghosts, and hungry demons creep in the darkness. The Heian (794-1192) period of ancient Japan was a time of great mysticism and magic. Set during this time period is a teenage girl who has wandered into a dark and gruesome castle, where mutated creatures and unimaginable horrors await. Together with multiple playable characters - exorcists ("Onmyoji") sent by their master to uncover the castle's mysteries - the young girl must master the powers of exorcism and Heian-period weaponry to survive the nightmarish world of psychological horrors.