DNA² follows Junta Momonari, a high school student who suffers from a condition that makes him vomit whenever he sees a girl in a swimsuit. His life changes when a time traveler named Karin arrives from the future to stop him from becoming the "Mega-Playboy," a legendary playboy responsible for overpopulation in her time. However, Karin accidentally shoots him with a DNA-altering "dud" bullet that actually activates his playboy genes, making him irresistible to women while still retaining his original shy personality as a separate clone. The story balances comedic chaos as Junta struggles with his dual identities and a love triangle between his childhood friend Ami and the cool, mysterious Tomoko, while Karin desperately tries to reverse the changes to save the future. Readers enjoy the series for its energetic romantic comedy, the inventive sci-fi twist on shy-guy tropes, and the slapstick humor mixed with genuine moments of heart, all central to Masakazu Katsura’s signature style.