Severe masochist Riu Matsuoka is forced to endure a daily life of torment blending pleasure and pain, compelled to face it all with a constant smile. This is a documentary of her intertwined agony and ecstasy, where primal instincts run wild. Whispering, "If I'm going to climax anyway, I'd rather be smiling," her smirk during each torture session reveals the pure, genuine charm of a true-born masochist. So overwhelmed she gets aroused even from slaps, she writhes with suppressed moans, unable to contain her emotions as she fights off the premonition of orgasm, repeatedly teetering between restraint and release. This contradictory state weaves an unparalleled eroticism.