Yamada, a fifteen-year-old first-year high schooler, sets herself a goal of one hundred casual partners, yet she is a virgin who panics at every opening. To get past her nerves she goes looking for an inexperienced first partner and settles on Takashi Kosuda, a plain, awkward classmate. Her clumsy seductions keep backfiring across four-panel gags, and despite herself she starts to actually fall for him.