Koi to Karada no KyoukaisenLove And Body's Borderline; 恋とカラダの境界線

Right after he was dumped, Tarou got a call from his newly-wed older sister, asking him to babysit her husband's teenage son. Tarou arrived to find a disrespectful 17-year-old kid who seemed to hate his guts. How would Tarou cope with the situation?