From Up On Poppy Hill (2011)
Based on the 1980 serialized manga From Up on Poppy Hill written by Tetsurō Sayama and illustrated by Chizuru Takahashi.
Umi Matsuzaki is a 16-year-old high school student living in Coquelicot Manor, a boarding house overlooking the Port of Yokohama in Japan. Umi's father has passed away and her mother, Ryoko, is in America studying so Umi helps clean and cook for the boarders and look after her sister and brother. Each morning, Umi raises a set of signal flags with the message "I pray for safe voyages". A 17-year-old boy, Shun Kazama, always sees this flag from the sea as he rides a tugboat to school and responds to them, but Umi doesn't know that. Several of the boarders include Miss Sahurah, Miki a doctor and Sashiko an artist.
One day, Shun writes a poem about the flags being raised which is published in Konan Academy's newspaper. At first, Umi gets the wrong impression of Shun as he does a daredevil stunt on behalf of the "Latin Quarter", an old building housing their high school's clubs that's being threatened with demolition. Upon her sister's request, Umi accompanies her to obtain Shun's autograph at the Latin Quarter. She learns Shun and the school's student government president Shirō Mizunuma publish the school newspaper. Umi convinces Shirō and Shun to renovate the Latin Quarter, and all the students contribute, both boys and girls. Umi and Shun start developing feelings for each other.
At Coquelicot Manor, Umi shows Shun a photograph of three young naval men. One of them is her deceased father, Yūichirō Sawamura, who was killed while serving on a supply ship during the Korean War. Shun is stunned to see he has a duplicate of the photograph. His father admits that shortly after the end of World War II, Yūichirō arrived at their house one evening with an infant, Shun. The Kazamas had recently lost their newborn, so they adopted Shun. This appears to imply that Shun’s father is Yūichirō, making Umi his sister. At first, Shun tries to avoid Umi, then he finally tells her they are siblings. Umi and Shun repress their romantic feelings and they continue to see each other as friends.
The renovation of the Latin Quarter is complete but the Kanagawa Prefectural Board of Education decides to proceed with the building's demolition anyway. Shirō, Shun, and Umi take the train to Tokyo, which is preparing for the 1964 Summer Olympics, and meet with Tokumaru, the school board's chairman. They successfully convince him to come inspect the Latin Quarter. Umi later professes her love to Shun, and he reciprocates in spite of their situation.
Having just returned from the United States, Ryoko tells Umi that Shun's father was actually Hiroshi Tachibana, the second man in the photo. She further explains that in 1945, Tachibana was killed in an accident on a repatriation ship. Shun's mother died in childbirth, and his other relatives were killed in the bombing of Nagasaki. Ryoko was unable to raise Shun, as she was already pregnant with Umi at the time. Yūichirō registered the child as his own to avoid leaving Shun as an orphan in the confusing postwar years, but Shun was eventually given to the Kazamas.
Tokumaru visits the Latin Quarter and, impressed by the students' efforts, cancels the demolition. Amidst all of this, Shun's foster dad tells Shun that the third man in the photograph will be able to tell him about his father. He is then told that an old sea captain, Yoshio Onodera, a friend of their fathers, currently is in Yokohama. But his ship departs soon, so Umi and Shun rush to the harbor, board the tugboat, and sail to him. Yoshio reveals to Umi and Shun the truth about their relation. Hiroshi Tachibana is Shun's father and Umi's father were very good friends with him, which is why Umi's father took Shun in. This means that Umi and Shun aren't related in blood, which means that they're free to be together. Yoshio explains that he'd had been close friends with Yūichirō and Hiroshi, and that he was away at sea when they were killed.
With everything resolved, Umi returns to Coquelicot Manor. She resumes her daily routine of raising the flags, but now, it's not just for her father.
TRIVIA
Easter Egg(s)
When Shun asks his father about his biological father, a ship named Kogenai Line, drives past Akio's boat. This ship is similar to the one in Ponyo.
On Yoshio Onodera's ship Koyo Maru Yokohama, there is a cabin with "Ghibli" written on it.