The story is written from two different perspectives. One is 16-year-old Vivi, a bright and extroverted young woman. The other is Jonah, who is 17 years old, quiet and serious.
Vivi and her mother are house-sitting for a friend in the quaint California beach town of Verona Cove. Vivi has fallen in love with its small-town charm. She also has been recently diagnosed with a bipolar disorder. But as the novel opens she decides not to take her medication as it causes her to feel like a zombie; she loves life too much not to experience it. Each day, she makes a trek to a cliff and throws her pill into the ocean. Although she has only been in town a few weeks, Vivi gets a part-time job at a pottery-painting studio. That’s where she meets Jonah.
Jonah’s life turned upside down several months ago when his father died of a heart attack. Since then, his mother has fallen into a deep depression, rarely able to drag herself out of bed. Jonah and his two older siblings, Silas and Naomi, take care of the three youngest children, including 6-year-old Leah.
They meet Vivi when Jonah takes Leah to the pottery shop as a reward for doing all her chores. Vivi is immediately smitten with Jonah’s good looks and soulful demeanor. Leah falls in love with Vivi’s fun personality and asks her over for dinner, because Jonah is the best cook in the town. Although Jonah is terrified what this beautiful girl might think of his loud, bickering, grieving siblings, he agrees to cook pizza for Vivi that evening.
She charms the entire family, except for Naomi, who tends to mistrust everyone. The following day, Vivi brings a homemade slip and slide to Jonah’s house, and the family spends a day laughing in the water. When Jonah, who works as a cook for the family’s restaurant, brings Vivi lunch at the pottery studio, she thanks him with a kiss. Even after Jonah tells her about his mother’s battle with depression, Vivi continues getting to know him and cheering up his family.
Unfortunately, the longer she does not take her medicine, the more manic her behavior becomes. She insists Jonah accompany her on a midnight ocean swim, even though it is illegal and dangerous. She paints the ceiling of her rented bedroom dark blue with stars. She also convinces her mother to let her borrow the car and then drives to San Jose. There, she buys herself a Vespa, because she thinks she will look cool riding it on the streets of Verona Cove. Her mom suspects she may not be taking her medication, but Vivi convinces her that everything is all right.
Some of Vivi’s ideas are good, such as when she convinces Jonah to think of ways to save his father’s restaurant from foreclosure. At first Jonah is reluctant, thinking that any change will dishonor his father’s memory. But Vivi argues that he will be adding to his father’s legacy, not dismantling it. Jonah begins to make plans to renovate the outside patio into a dining room instead of a storage area. Vivi also helps Jonah’s mom when she suffers a panic attack at the local grocery store.
Vivi’s behavior becomes more erratic at the town bonfire. She is openly hostile to Ellie, an old family friend and the daughter of the man who owned the restaurant with Jonah’s dad. Then she insists on going skinny-dipping with a bunch of the locals. Jonah is furious as she flirts and takes pictures with strangers in her underwear.
The two argue, but Vivi shows up later in his bedroom while the rest of the family is asleep. She explains that she values experiencing life over people, but she wants to share every experience she can with him. They have sex, and Vivi leaves before dawn.
Jonah hosts a party for Vivi’s 17th birthday on the patio of the restaurant. Everyone dresses as his or her favorite animal, per Vivi’s wishes. Jonah wears a tuxedo and says he is a penguin. Later that night, Jonah opens up about his father. Vivi begins a frantic search for her own father, a man she has never known. She ransacks her mother’s bedroom and finally finds her birth certificate, which lists her father’s name. She finds another document that he signed, surrendering his custody of her. It said he was from Berkeley, California.
Vivi imagines how thrilled her father will be when she finds him. She rides her Vespa down to Berkeley and knocks on his front door. But instead of a happy reunion, she finds out her father does not want her in his life and has never told his family about her. Vivi breaks down in tears and calls Jonah to bring her home.
Vivi’s mother buys her a dog to help revive her from her depression. She begins to feel like the universe is sending her on a special quest. She searches for clues throughout the town. She gets the idea that the next clue will be found in San Diego. As she races out of her house to find it, she runs into Jonah. He is worried about her behavior, but agrees to go for a ride with her on the Vespa.
Once she begins speeding through stop signs, he makes her let him off. He tries to convince her to let him drive her home, but she refuses. In her manic state, she loses control of the Vespa and hits a tree. She wakes up in a hospital on heavy medication with a compound fracture of her arm and severe road rash.
When Jonah tries to visit her in the hospital, she throws him out, convinced he should be angry with her. Instead, he goes home and bakes her a pie. The next day, Ellie delivers the pie and a gift basket from Jonah’s family. She and Vivi have an honest talk about the nature of mental illness, as Ellie’s brother had been a patient in the same hospital when he battled depression.
After this, and a visit with a psychiatrist, Vivi begins to understand that accepting her diagnosis, and working with her doctor to find the right medication, will allow her to live a full life. It may not always be the life she dreamed of, but it can be a rewarding life, nonetheless.
Jonah’s mother also begins to get help for her depression. She starts working on improving the financial situation of the restaurant. Ellie and Jonah have developed some new items for the menu, giving the restaurant more of a bistro vibe. They introduce the new menu to their local friends and receive rave reviews.
Vivi arrives once everyone but Jonah has left. The two walk out to their favorite spot overlooking the ocean. There she tells him that she is returning to her home in Seattle. It is there she believes she can get the help she needs to learn to live with her disorder. Jonah is devastated. She agrees to meet him the next day before she leaves town so that they can say goodbye.
When he arrives at the meeting place, he finds Vivi has left him a note. She explains how much she loved him, but that she hates goodbyes. She has left him a present on the restaurant patio. She has painted a mural on the outside wall.
At first, Jonah thinks it is only a beautiful seascape, but then he realizes there are seven small sailboats with nautical flags that spell out his last name. An eighth, and larger sailboat, is sailing toward a glorious sunset. Jonah knows Vivi has painted a portrait of his family. His father is moving forward to a glorious unknown destination, but his family will follow him one day.