|Media type||Print (Hardcover)|
Martha goes away every summer from her home in Wisconsin to visit her grandmother, Godbee, on the Atlantic Ocean. One year, she receives an journal page from a woman whose daughter, Olive, has died. Martha did not know Olive very well, though Olive admired Martha from afar despite never speaking to or hanging out with Martha. After reading Olive's journal page, Martha regrets how she had not been nice to Olive and discovers they had a lot in common, particularly a love of the ocean and a wish to become a writer.
When Martha's family arrives at Godbee's house, an argument between Martha's parents causes tension between everyone in the family. Martha distances herself from her family out of anger and becomes closer to Godbee. They decide to share one secret about themselves every day of Martha's stay. In the meantime, Martha also begins to write a story about Olive as a memorial.
During her stay, Martha develops a crush on Jimmy, one of the Manning boys living nearby, who are friends with Martha's older brother Vince. When she tells Godbee about her crush, her grandmother tells her to be careful. Martha decides to add Jimmy to her story about Olive, renaming him James. Jimmy is revealed to be interested in film-making and is trying to make a film about "life," covering different facets such as family, death, and love. As she spends more time with Jimmy and accompanies him as he records various things for his project, Martha contributes with an interview and tells Olive's story for the "death" portion. As part of the "love" section of the film, Jimmy spontaneously sets up his camera on the way back home and kisses her. Martha is shocked when she learns that Jimmy tricked her as part of a bet with Vince and the other Manning boys as to whether he could get her to kiss him on camera before they come back from sailing. She runs off in tears and scraps the portion of her story about Olive and James. Tate, Jimmy's younger brother, apologizes to Martha for his brother's actions.
As her stay at Godbee's house draws to an end, Martha fills a jar of ocean water to give to Olive's mother to fulfill Olive's dream, which had been to see the ocean for herself as "Olive's Ocean." Martha also decides to abandon her story about Olive. After Martha says goodbye to Godbee, Tate gives her a bag and a note where he apologizes again for Jimmy's actions and confesses that he likes her. When she gets to the airport, Martha finds Jimmy's tape inside the bag.
Back in Wisconsin, Martha goes to Olive's mother to give the ocean water to her, only to find that Olive's mother had moved to Washington or Oregon. Martha writes 'Olive' with ocean water on the front step of Olive's house until the water runs out. Martha stays until the sun dries up the word 'Olive'. And Olive, who had been in her mind a long time, is finally forgotten. Martha then returns home to her loving family.
- MacPherson, Karen (August 18, 2011). "Top children's authors offer winning reads". The Detroit News.
- Asai, Rummanah (September 29, 2011). "Books in the Spotlight - Banned Books Week 2011: Olive's Ocean". Retrieved September 26, 2014.