In a run-down apartment building in Kitashinjuku called "Sakura-so," lives an erotic beauty named Eri-chan in room 110—a particularly old unit lacking even a bath. She gets turned on by virgins, nerdy salarymen, and even the middle-aged men living in the same building, especially when they return from the public bath. Whether day or night, she picks up men coming back from the bathhouse, luring them into her room and indulging in a sexually charged daily life.