Mantarō Nishino is a mild-mannered salaryman employed in the stock industry. He possesses an exceptionally large penis, anthropomorphized as a highly libidinous gopher. This physical attribute regularly triggers accidental exposures where women become captivated upon sight, inevitably leading to sexual encounters. These interactions involve Western adult film actresses, a geisha-style woman, and a corpulent female yakuza boss.

Despite his unassuming demeanor, he wields his physical feature as an unconventional weapon within comedic contexts. The narrative interweaves his professional stock market environment with erotic incidents, frequently shifting between corporate boardroom settings and sexual episodes. His actions primarily propel the plot through inadvertent revelations and the ensuing reactions of female characters. The story positions him as a conduit for exploring themes of sexuality intertwined with the stock market, framed within a farcical context.