Kana, a young married woman, begins working to support her household after her husband loses his job, leaving her mentally strained. With their relationship growing colder and intimacy fading, she is seduced by her boss, Asano, who forcefully takes her lips. His tongue invades her mouth, raping her orally with deep, intense kissing, and she gradually succumbs to the pleasure of tongue penetration. Unable to forget the sensation, she starts masturbating frequently. Eventually, in secret from her husband, she begins craving slow, saliva-dripping kiss training, entwining her tongue passionately, becoming completely addicted to intense kissing sex.