Hayato Hiiragi and Tsukasa Terada are next-door neighbors who had shared a close relationship as children. Although the two still spend time together, Hayato no longer likes to meet the other boy's gaze. Tsukasa cannot fathom what changed between them, but he notices that there are only a few people whom Hayato will look in the eye—as for the rest, eye contact never lasts longer than five seconds.

The truth is, Hayato can copy the sexual desires of anyone whom he locks eyes with for five seconds. Then, for 24 hours, he will experience the same pleasure they receive through engaging in intimate acts alone or with a partner. Hayato alternates between viewing his body's condition as a blessing or a curse, but he is unable to achieve release by any other means.

Be it men, women, or even animals, Hayato can copy them all. But other than a single incident in their past, he has resolved to avoid using his ability on Tsukasa. When, one day, Hayato accidentally stares too long at a stray cat reflected in a mirror, he is not prepared for her to go into heat afterward. Overwhelmed by the desire to be impregnated, the first person he accosts amidst a haze of lust is Tsukasa!