As we meet Junta for the for the time, we can see that he is just an "ordinary boy" (you know the obligatory ordinary boy you see at the beginning of most anime). In fact, he is kind of sub-ordinary! You see, he has this strange condition that makes him feel queasy when he is aroused. Basically he vomits buckets when he sees a bit of exposed female flesh, or when a girl comes on to him. Hence, Junta is something of a laughingstock for girls. The exception to this rule is his best friend Ami Kurimoto who has known him since childhood. Now Junta has no idea that he is destined to become the Mega-Playboy responsible for the Japan's future overpopulation. At first, the DNA Operator Karin is taken aback at how unattractive and uncharismatic Junta is. Nevertheless, after a brief chat with him she shoots him with the DCM bullet. Unfortunately it's the wrong bullet and instead of suppressing his dormant Mega-Playboy DNA, its development is triggered and accelerated! Junta is extremely confused by all this, all he knows is that he's head over heels for the beautiful and mysterious Karin. After being shot, his Mega-Playboy alter-ego would surface every now and then. In this mode, girls find him irresistible, Karin included. The only exception is Ami, who likes Junta as he is and hates the Mega-Playboy persona. Much hilarity, adventure, surprises, and heartbreaks ensue thereafter.