Hiiro no Uta

After the death of her beloved grandmother, Chika became involved in a series of mysterious incidents. She was also being followed by a mysterious man named Sei. It seems that this man might know the reason why strange things have happened to Chika...? At first, Sei offered some kind words to Senka, who was distressed by the supernatural events. However, right after that, he suddenly and unexpectedly made a surprise attack and kidnapped Chika...?

(Source: Akita Shoten, translated)