Fleeting Memories

While walking on the streets of Tokyo Japan to his home, Kurayami Shiro suddenly gets an extremely painful headache. There, on the streets, he passed out. The people quickly called an ambulance, and with his cellphone, they called his guardian.

Shiro is a (17) year old highschool student, living with his older sister in Tokyo in an apartment. His older sister, Kurayami Aoi (19) became his legal guardian when their parents died from an unknown reason. Unfortunately for both of them, nobody from their relatives were willing to take them in, so both of them were forced to become working students.
Shiro's only goal was to find out how their parents died while Aoi supports him from the background. -At least, that was the original plan, until unpredictable events started happening.