A fresh-faced gravure idol with a refined, well-bred aura, Mari Kosaka, makes her debut. The mole under her eye exudes a striking, seductive charm. Despite being her first work, she dives in with an unexpected "overboard mode" in full swing. At first, she seems a bit overwhelmed by the excessive direction of her first shoot, but Mari-chan's efforts to respond with a smile are just too cute. Then, her hidden true nature suddenly emerges, leaving the staff stunned: "Could she be a total masochist!?" Despite her innocent appearance, she unleashes unrestrained, erotic reactions as if a switch has been flipped, and the gap is relentless. Tension and shyness give way to a burst of pleasure triggers blooming all at once. When a trembling toy is applied to her immobile body at the end, she transforms dramatically. Gasping in a high-pitched voice, "Ah, ah, ah, no, gyaa!" she climaxes repeatedly in a shocking display. Mari Kosaka's striking debut, carrying out the overboard direction to the very end. The explosive contrast between purity and aggression makes this unforgettable Overboard Debut a must-see.