Inexperieced succubus Saki tries her best to make her first harvest a special occasion, but it goes so wrong that Rento's left with side effects downstairs! Good thing Saki's big sister is a doctor. But Yumeko takes no half measures - she wants to cure Rento of his virginity as well as his symptoms. Has Saki finally found a donor she truly loves? And which succubus sister will have her hunger sated at last?