People who tried to get Hangestu Ye-seul Tsukishima to meditate were met with frustration. Letting his mind go blank was unnatural. He had to think at all times because he knew he lacked any natural intellect, not like his grandmother and father who were naturally gifted.
The only times his mind was turned off was when he was immersed in a task. Walking, cooking or wiping the dust off of the window blinds of private eye Tae-yeon choi.
Too many thoughts clung to his brain like dust motes which required dusting. As he wiped away the literal dust so did the metaphorical dust disappear.
For a bit.

There was a woman that refused to leave his mind and much to his frustration it wasn't the air acolyte he was dating, it was someone mysterious and vexing; an author by the name of Omoi Tenoh. His girlfriend was a fan and his sister considered herself a rival to the popular author despite the stark differences in style and genre but what took Hangetsu from mild interest to insomnia-inducing obsession was how any investigation into the author's life was met with blockade after blockade.
His grandmother, who had taught him everything he knew about being a detective also taught him the joy of solving a mystery and how that joy intensified the more difficult it was and Omoi Tenoh was a difficult mystery.

People left traces. It had nothing to do with being clever, he'd dealt with clever criminals before but they had lives and existences he could verify...finding out anything about Tenoh was like grasping at a plume of smoke.
He had a few things to go on. She was female, particular about her tobacco and while it was by no means a solid fact Hangetsu had a feeling she had leanings toward police work at one time.

Unconsciously Hangetsu was cleaning the ashtray on the desk of the detective he volunteered to assist when he realized how little cleaning had helped him forget. Considering how dirty the rag he used to dust had gotten and how clean the office was he wondered just how much time he had been lost in thought.