From Turtle Paradise:

16-year-old Kizuna stalks the city at night, flirting with middle-aged salary men and coercing them out of their money. The thrill should be enough to satiate her, but Kizuna remains unsatisfied with her everyday life… That is, until the beautiful Inoue Yuki, also living in “Birdcage Manor” approaches Kizuna with a job proposition- to model in the nude for Yuki’s cousin, a painter and fellow resident Yusei Asai!