At the isolated all-boys Kanenone Academy, high schooler Yuusuke Takasaki spends his days with the self-styled Baka Trio until the school agrees to a month-long co-ed trial with a nearby girls' school. When the bus of visiting students arrives, Midori Chitose leaps out and hugs a bewildered Yuusuke before he can even introduce himself. This light novel adapts the Green Green visual novel, the same source the 2003 anime series was built from, and follows the shaky first weeks of the trial run.