"Kotori, you're so sensitive."
Takanashi, a college student, is being forced to live with (*be surveilled by) Kai, a bill collector, because of his father's debt.
Kai gives him the nickname "Kotori" because of the "little bird" characters in the name "Takanashi," and Takanashi gets fed up of having days of Kai showing up at his school and part-time job.
Plus, Takanashi now has nothing like privacy because Kai just opens the door when Takanashi is in the bath and Kai's bugged his apartment.
In the end, Kai secretly watched him jacking off in his bathroom!
The strange living situation between a twisted yet caring bill collector and the emotional, hot-and-cold college student has begun!