At 44, Charlene (Charley) Hempstead finds herself in a strained relationship with her live-in boyfriend of 20 years, Michael. He wants to get married, but Charley needs time to process the loss of her job and the imminent death of her sister, Meg, from breast cancer. When Meg asks Charley to open up the family’s abandoned lake house so they can spend a summer together like they did when they were kids, Charley cannot refuse.
She heads off to Minnesota and begins the renovations to make the house habitable again. It has been vacant for decades after the tragic drowning of their younger sister, Bunny. Their mother, Louise, refused to let anyone use the house after that summer. The tragedy also led to the dissolution of the once close Hempstead sisters and their families.
Louise rarely speaks to her sister, Jo. Jo’s youngest daughter, Beverly, Bunny’s best friend, wound up needing psychiatric therapy for several years and living in a foster home. Beverly’s older sister, Krista, served 20 years for killing a man, and the eldest sister, Hope, left to live with her grandparents. Meg had a psychotic breakdown after the drowning and forgot the entire year after Bunny’s death. Although she eventually healed, she forever mourned the loss of her close family ties.
While Charley fixes up the house, Meg writes letters to her grandmother, aunt and cousins, and invites them to house for whatever time they can in the summer. Aunt Jo will not come unless Louise gives her permission. Hope writes back that she would love to come with her two daughters, but their time is so busy, she will not know the exact dates for a while.
Hope has spun a delusional world in which she is still happily married. In truth, her husband, Frank, left her six years ago, remarried and has a son with his new wife. Their teenage daughters, Trude and Bobbi, live with their father because they cannot deal with their mother’s refusal to accept reality. Hope had gone to live with her grandmother and grandfather, the judge, after Bunny died. She wanted a life of privilege and money, and the judge was more than happy to supersede her parents and give it to her, as long as she lived by his rules.
Charley is surprised one afternoon to see her cousin, Krista, sitting outside on a lawn chair. Krista has been released from prison, but wondered if the cousins really wanted her to stay with them. Charley insists she is welcome, and they catch up on their lives. Charley admits to having found the daughter she bore out of wedlock. She got pregnant just before Bunny drowned. The father was a boy she dated over the summer whom she was never able to locate. Krista used her time in prison to undergo therapy and take classes.
Krista is thrilled to re-establish ties with Meg and Charley, and even more, to reunite with her mother, Jo. Krista gets a waitressing job at a resort on the lake, even after admitting her felony record to the manager, Jake. She fits in well with all the staff and patrons of the resort. Jake often walks her home after work and the two begin a tentative romantic relationship. He accepts her past because he has made many mistakes of his own.
Hope arrives at the house a few weeks later with Trude and Bobbi. Krista confronts Hope about her lack of honesty. Hope admits she would not have come to the house if she had known Krista was there and wanted to settle their differences. She had come believing Grandma Berkey was on her deathbed and wanted to settle everyone’s inheritance.
Trude and Bobbi plot to run away that night and get a plane back to their father. Unfortunately, a drunk driver hits them before they reach the airport. Bobbi is flown to a trauma hospital in Saint Paul while Trude is sedated and recovers with only minor injuries.
Charley calls Frank, Hope’s husband, to tell him the news. He tells Charley to keep Hope from the girls but that he will be there soon. Hope stays in the waiting room while Charley visits Bobbi. Her niece then tells her about Hope’s bizarre behavior.
In the waiting room, Hope talks nonstop to an unconscious man, making up stories about her husband and children. Hope is admitted for psychiatric evaluation. When Frank arrives, he is glad to hear the girls will make a full recovery. He and Charley try to sort out the truth from the lies Hope has told over the years.
Jo goes to visit her sister, Louise, demanding that they mend their differences so they can restore the family. Over drinks, the sisters relive the weeks before Bunny’s death. Jo’s husband, Roy, was handsome but a rogue. He wanted quick money and always lost it gambling on various business ventures or drinking it away.
His brother, Carl, who was married to Louise, always bailed him out. That last summer, Roy brought a business associate to the lake. Ivan spoke with a foreign accent and was dashing and intriguing. He claimed his companion, Corky, was a family friend. Ivan stayed in the boathouse while Corky slept in the main house.
Roy left Ivan and Corky at the lake while he returned to work. Over the next few weeks, the dashing Ivan wooed Louise. Although content in her marriage, Ivan spun romantic tales of them running away to live on a tropical island. Jo began to worry her sister might actually jeopardize her marriage and have an affair.
One night, Jo hid under the boathouse and heard Corky and Ivan having sex. She overheard them talking about conning Louise out of her money. Jo confronted Ivan after Corky left. He attacked her, forcing her on the bed, but Louise heard her screams and hit him over the head with an oar. The women panicked when they could not find his pulse.
Convinced they killed him, they put his body in his car and drove it into the lake. Then they told Corky that he left her behind when they discovered the con. They dropped her off at the bus station. Once home, Louise began to suspect Jo of being in on the con. Now that Louise murdered a man, Jo and Roy had something to hold over her so she would forgive all the money they had borrowed from her and Carl over the years.
Less than a week later, Bunny died, and the sisters never spoke again about what happened that summer. Louise later discovered that Ivan survived, but claimed to have amnesia when he showed up at a local hospital with a head injury. Jo is surprised to learn that Louise has been hoarding all their mother’s belongings in her house so that whenever Jo needed money in the future, she could sell them to help provide for her.
As the sisters begin their path to reconciliation, the cousins begin their healing as well. Hope remains under psychiatric care. Krista discovers that Jake is actually the father of Charley’s daughter. Charley holds no grudge against him, and he is determined to get to know the daughter he did not know he had.
Jake and Krista continue their relationship with the hope it may lead to marriage. Charley reconciles with her boyfriend, and the two finally get married. Early in September, Meg passes away from cancer surrounded by her loving family.