Nangoku Prison ~Hyouryuu Shita Mujintou ga Kozukuri Shinai to Derarenai Shima Datta Ken~

Reijirou finds himself stranded on a deserted island with three beauties: Teen idol Nasu Arina, her manager Natsuki and his student Yume. Arina sees a golden opportunity to lose her virginity to her beloved 'sensei' but Natsuki will do anything to protect her. Throwing herself at Reijirou in hopes he'll use her body instead but her plan fails. Arina is desperate to throw off the shackles of chastity and she will not be stopped.

After mating with all three girls he learns that they aren't as alone as they thought when they discover two sisters are also trapped on the island Hatsuho and Minori Nawashiro. Five girls and one man with no society and no rules; it's time to breed!