Saki Midorikawa is a renowned pop singer celebrated for her openly lesbian identity and attraction to beautiful women. She forms an intense romantic obsession with emerging singer Kaori Shiina after meeting her at an event. Discovering Kaori's intersex condition during a bathroom encounter, Saki blackmails her into a sexual relationship by threatening to reveal this secret publicly, exposing her readiness to exploit vulnerabilities for personal gain.

Her motivations are deeply shaped by her history with Yuko Imai, Kaori's manager and Saki's former lover. Years prior, both endured sexual abuse from industry figures while supporting each other as aspiring singers. After Yuko abruptly exited the industry without explanation due to a vocal cord infection, Saki clung to unresolved bitterness over this perceived abandonment.

To resolve her conflicting desires involving Kaori and her lingering resentment toward Yuko, Saki orchestrates a sexual competition through partner swapping, challenging each to make the other climax first. Saki loses when Yuko exploits a weakness in Saki's partner, Sayaka Tamura. Despite this defeat, Saki continues pursuing Kaori and joins her and Yuko at their office, showcasing relentless romantic fixation and refusal to surrender.

Saki's personality fuses overt sexuality with calculated manipulation, consistently employing intimacy as a mechanism for control while nurturing past grievances. These traits perpetually drive her actions.