Sakurai Toshifumi

On the eve of his seventeenth birthday, Haruo was hoping to finally lose his virginity. But the morning of his birthday, a big surprise awaits him: he wakes up with his room submerged by water! No time to think, and to avoid drowning, he is obliged to take refuge... in a bathtub! Worse than all, he is stuck in it, next to his big brother whom he hates viscerally. Will the two of them be able to survive the rising sea level, while the whole earth seems to be in danger? And how far will their makeshift boat take them?

The story starts off on a deserted island with a woman shouting "I ain't a chick!" while being chased by 100 male perverts in underwear!!! Then it cuts back several hours earlier and we get to see how 'she' got into this situation. It's a desperate struggle of survival on a deserted island between this woman and the different groups of men who are pitted against her, some of whom might turn out to be allies.