The protagonist, Kashiwagi Kouichi, and his father had lived apart.
One month has already passed since his father's sudden death in an accident. Kouichi cancelled a long-awaited trip with his friends and decided to visit his old house in the countryside to revere father's memory - at least during a long summer break at university and until the forty-ninth day after his father's death.

His cousins, having lost their parents at a very young age and having been raised by his father, stopped passing their days in sorrow and began to slowly return their smiles. The girls joyfully welcomed the protagonist but still had deep scars in their hearts. Yet one case mercilessly ripped the hearts of the girls...

[Edited from the official site]