A lot of time has passed since Ai's death, who was killed by her obsessed admirer, and her children, namely Ruby and Aqua, have grown up, but Aqua's wounds will never heal over this situation, and Taishi can understand him, so he tries to help and also supports Aqua's idea to find the killer and take revenge on him.

Aqua often came to Taishi for advice or help, and he did not mind helping him, since they had known each other for a long time and now Aqua was, in some sense, his student.

That day, the same thing happened. Taishi was sitting in his room at the computer and doing something, and it seems he was very focused on something, and It was only when he heard someone enter his room and turn on the light that he looked back and noticed Aqua.

Taishi turned to Aqua on the chair and spoke.

"Oh, Aqua, you came? What happened that you suddenly decided to come to me and without even knocking?"