The following version of this novel was used in the creation of this study guide: Weiner, Jennifer. The Summer Place. Atria Books. 2022. Hardcover Edition.

Part One begins as Ruby and Gabe announce their engagement to Ruby’s family. Her stepmother Sarah, however, is terrified that Ruby is getting married too early, but pretends to celebrate so she does not drive Ruby away. Years before the beginning of the novel, Sarah married Ruby’s father, Eli. Over time, Ruby and Sarah became close, and Ruby even developed a relationship with Sarah’s mother Ronnie. Still, none of them question Ruby’s engagement, unaware that Ruby wishes they would stop her because she thinks she is making the wrong choice.

Meanwhile, it is revealed that 20 years prior while Eli's wife, Annette, was pregnant with Ruby, he had an affair with a woman that claimed to be named Jane. When she came to him for money to have an abortion, Eli provided it and the two never spoke again. However, it is revealed to the reader that Jane’s name is actually Rosa, and she scammed Eli for abortion money, as she did not think she could be a mother. When she got the money, however, she kept her son, Gabe, and did not realize Ruby was Eli’s daughter until the engagement. Neither parent tells their children the truth, even though Eli worries Gabe may be Ruby’s half-brother.

Meanwhile, her mother Ronnie is excited to invite the family to the beach house for the last time as she plans to sell it after Ruby’s wedding. When her sister Suzanne sends her children Sarah and Sam an ancestry kit, it is revealed that Ronnie actually cheated on her husband, Lee, just before they married and she is not sure if Sarah and Sam are his or her affair partner's. Instead of telling anyone the truth, Ronnie gave up her publishing career, as she hated the cruel woman she was as a professional writer.

Around this time, Sarah’s twin brother Sam is excited to meet with the family alongside his stepson Connor, whom he adopted after the death of his wife, Julie. Sam, who has spent his entire life adapting his desires to those of others, is determined to get answers from his mother at the wedding.

As the family prepares to go to Cape Cod for the wedding, Sarah feels that her relationship with Eli is falling apart, as he refuses to tell her about the affair, even though they were not married‌. Meanwhile, Sarah spends more time at a personal apartment where she practices piano when nobody is listening.

In Part Two, Ronnie prepares for the wedding when she learns that she has a tumor in her stomach.

Meanwhile, Sam officially becomes Connor’s legal guardian. After many months of grieving Julie’s death, Sam is shocked when he becomes aroused by gay literature and artwork. So, he explores his sexuality with a new friend named Tim and decides he will tell his family after the wedding.

At the same time, Sarah becomes more frustrated with Eli’s distant personality, unaware that he is frantically trying to figure out if Gabe is his son. Touch-starved and deprived of the affection she needs, Sarah has an affair with her first love, Owen, whom she met as a child and dated briefly when they were teenagers. The two decide to meet in Cape Cod again.

Part Three starts as everyone arrives at the Cape Cod house and Ronnie announces ‌she is selling it after the wedding. She also reveals her own infidelity to Sarah, but does not tell her that she is dying of cancer.

The night before the wedding, Ruby breaks down and calls it off, running into her mother, Annette, who takes her to a nearby hotel to rest. It is then revealed that Annette never wanted to be a mother, but was guilt-tripped into keeping the baby by Eli who promised her that she could have the life that she wanted. She hopes that Ruby can find happiness in her life, with or without marriage.

Meanwhile, Sam meets a man that calls himself Anthony at a gay bar and feels instant chemistry when the two sleep together. Later, he realizes that the man is actually Ruby’s former fiancee, Gabe, and the two decide to pursue a secret relationship as they make each other happy.

The next day, Eli is thrilled to learn that Gabe is not his son and hugs Rosa, unaware that Sarah is watching. Assuming that he is cheating on her, she sleeps with Owen next to the pond, only to realize that he lied to her about his previous relationships and hopes she will buy his family’s land. Sarah returns with the intention of fixing her marriage just as Ruby and Annette arrive home.

However, Ronnie passes out and is rushed to the hospital where the family learns that she has a tumor and very little time left to live. Eli apologizes for how he treated Sarah and promises to make it right, and Sarah does not tell him about her own affair as they embrace.

One year later, the family gathers to scatter Ronnie’s ashes on the beach. Sam and Sarah announce that they are going to keep the house for future generations. In the end, the home welcomes Ronnie’s spirit, and the two watch the family they love.