Dora, Carson and Harper have the same father, but they have little in common with each other. The women are united only by childhood memories of annual trips to Mamma, her grandmother, who lives in an old house on the island. But this year the family meeting will have a new scenario. Mamma celebrates her eightieth birthday and invites her granddaughters to her place for the summer. However, they are forbidden to take children, husbands or lovers with them. What was the mistress of the house up to?