Eros d’O (Eros of O) - The Story of Lady O - Devilish Paradise

The story

Otoha, a music college student, takes flute lessons from Professor Atsushi Kono; she is completely dominated by his personality. Junya, a new acquaintance, moves in next door to Otoha. Instantly smitten, Junya invites her out for drinks with some friends. Although Otoha has no interest in men other than the Professor, she reluctantly agrees when he tells her he wants to watch her having sex with Junya. She invites Junya into her home, and they begin to have sex. The Professor watches every moment of their encounter intently on his computer via a webcam. Claiming he was "going mad with jealousy," the Professor binds Otoha, and she happily submits to it. Junya, having fallen genuinely in love with Otoha, asks to date her seriously, but she dismisses him, saying she already loves someone else. Otoha plays with a marionette—but before she knows it, the marionette has transformed into Junya...