Natsuki, who started working at a men's spa secretly because her husband's income was insufficient, even resorting to handjobs. However, one day, her despised father-in-law found out, and Natsuki, exploited by his knowledge of her vulnerability, was forced to provide rejuvenating massages that crossed a line! Humiliating oil massage handjobs, no-panties shameful fellatio, persistent cunnilingus leading to climax... Eventually becoming a sex-relief masseuse exclusively for her father-in-law, she ultimately succumbs to begging for his penis and accepts non-consensual sex, falling into an indefinite, free-for-all sexual servitude!