Harashima Naoto is a 20-year-old college student. His parents, Yuuji and Yumiko divorced when he was five years of age because Yuuji realized he was gay.
Yuuji has decided to "marry" Goro and introduces him to Naoto and Yumiko at a restaurant. Naoto and Yumiko are surprised to see Goro, who is a good-looking 26-year-old man.

One day, Yuuji asks Naoto to come to their place to stay during Yuuji's business trip. He says Goro wants to leave him and asks Naoto to keep an eye on him. Naoto visits his father's place to stay with Goro. Goro is nasty to him. Goro is an excellent cook, but doesn't cook for Naoto. Naoto asks Goro where he and Yuuji first met. Goro says they met in a bar where gay men go. Naoto asks him why he is going to marry Yuuji. Goro answers "Harashima Goro" sounds better as a jewelly designer than his Maiden name "Ebi(shrimp) Goro". Goro says he actually prefers young men. Naoto gets nervous. He makes sure his room can be locked and stays only a night. Later, Yuuji tells Naoto that Goro often lies.

When Naoto goes to a restaurant with Haruna, who he is in love with, Yuuji and Goro are eating lunch there. Goro introduces himself to Haruna as Naoto's elder brother. In the family registry sheet, Goro is Naoto's brother because Yuuji has adopted Goro to "marry". Haruna speculates Goro is Yuuji's step son.

Naoto goes to stay with Yuuji and Goro while Yumiko's boyfriend Ijuuin is staying at his place with Yumiko. Goro gives Naoto many rules to follow. He looks nasty, but Yuuji says he just wants to communicate with others.

One evening, Goro comes home from work and sees a man standing in front of the door. The man is Ijuuin. Ijuuin mistakes Goro for Naoto. When Naoto returns, Ijuuin thinks Yumiko lied she has an only son. Soon after that, Goro's elder brother, Hajime, visits them. Ijuuin thinks Yumiko actually has three sons. Yumiko also visits them.Yumiko says she and Ijuuin have broken. Hajime is a tall, good-looking man. He is 33 years of age and married with a daughter. He mistakes Ijuuin as Yuuji. He thinks Yuuji has a female lover with a son in addition to Goro and all of them live together. He encourages Goro to go back to live his mother and sisters.
Naoto tries to escape from the room, but Goro tells him not to leave him alone. Goro goes shopping with Naoto and cooks a lot of dishes.

Yumiko works for an insurance company. When she is out for a business trip, Naoto goes to Yuuji's place again to eat meals that Goro cooks. Yuuji is going to stay out at company's dormitory for work. The next day, Naoto visits Goro's office to see him. Goro's come out at his office, so office staff are interested to know who Naoto is. Another customer comes to see Goro. He is a middle aged man. He asks Goro to give the telephone number of the dormitory where Yuuji is staying. He is Yuuji's ex-boyfriend. Goro tells Naoto that Yuuji always eats out by himself since 10 days ago. Goro worries that Yuuji might love his ex-lover more than Goro. Naoto can't get why Goro, who is young and attractive, is not sure he can beat the ex-boyfriend, who is a fat, middle aged man. Actually, Yuuji's ex-boyfriend invited him to go to an esthetic saloon to lose weight. They spend every evening at the saloon together. Finally Yuuji's ex-lover finds out his boyfriend loves fat men and stops losing weight.

Goro's mother invites Goro and Yuuji home. Yuuji suddenly cancels the invitation due to his work. Goro visits his mother and sisters' place with Naoto. Goro's mother and sisters look beautiful. All of them encourage Goro to return to their house. When Naoto eats what they serve, he is about to throw up and leaves the room. He is lost outside of the dining room and opens a door. Unwashed clothes and other stuff beats Naoto like an avalanche. Goro's mother and sisters want him to go back to their place because he is a good cook and he does laundry and cleaning.

Hajime is in love with Yumiko. Goro's firm plans to make a subsidiary in Osaka and Goro might be transferred there. Goro talks about that with Yuuji. Haruna sees Yuuji and Goro kissing on the street. It's shocking to her because she believes Goro is Yuuji's step son. Naoto tells her the truth. Haruna says "Then there's no problem at all!"
The mother of Goro's sister's boyfriend doesn't allow her son to get married with Goro's sister because Hajime has an affair with Yumiko and Goro is gay. Goro visits the boyfriend's house with his mother and sisters. He says he is going to leave Yuuji and go to Osaka. The boyfriend's mother allows her son to marry Goro's sister. That is Goro's lie.

Hajime and Yumiko get married. Naoto stars living by himself.

Masayuki and Shinji are twin brothers. One day, when they were very young, Masayuki called Shinji in the garden. He told him to look into the room. They saw a strange woman crying there. Big white flowers were blooming in the garden.
Even though they were twins, Masayuki was called the first son and he behaved as if he was the elder brother. He was very nice to Shinji. One day, Shinji was crying because he had to leave his family to be an adopted child of another family. Masayuki said "If you don't want to go, I'll go instead of you." "Really?" said Shinji. A tall man took Masayuki somewhere very far.

Shinji is a junior highschool student now. He goes to watch the first preliminaries of a junior highschool students' piano competition with Mr. Andou, who is a music teacher in his school. After the preliminaries, he talks with Masayuki. They met two years ago for the first time after Masayuki was adopted. Shinji listened to Masayuki playing the piano and was very impressed because Masayuki was an excellent pianist.
Shinji: I'm jealous of you. Even though I said I wanted to learn how to play the piano, my parents didn't allow me to do that.
Masayuki: There's a piano in your house. You can practice by yourself.
Shinji: We don't have a piano.
Masayuki: Yes, you do. There was a piano in the room with a big window. I remember lilies were blooming near the room.

Returning home, Shiji asks his grandmother if there were lilies in the garden. Grandmother remembers there were lilies. Shinji asks if there used to be a piano in his house. Grandmother says there wasn't a piano. In the dream, Shinji hears someone playing Chopin's nocturne.
The next day, Shiji meets Masayuki. Masayuki says he will be playing Chopin's nocturne at the second preliminaries. Shinji takes Masayuki to Shinji's house because all the other family members are out. Masayuki says he remembers he looked into the room through the window with Shinji. " A strange woman was crying and there was a piano beside her." says Masayuki. "I don't remember that." says Shinji. "We were standing in the lilies. Mother got upset because our clothes were damaged by pollen." says Masayuki.
When Masayuki is coming out of the house, Grandmother sees him. She wonders why Shinji are wearing glasses at first, but she soon recognizes Masayuki.

Masayuki passes the second preliminaries but Shinji is sure Masayuki has some problem. Even though Masayuki will be playing Polonaise Heroica at the final competition, his arm has an inflammation of a tendon sheath. Masayuki has no intention of giving up playing at the competition. He has practiced years for the competition.

Grandmother sees Shinji crying in the dark.
Grandmother: How silly it is that a boy is crying here alone!
Shinji: Masayuki was adopted instead of me because I didn't want to.
Grandmother: You're wrong. We had asked the Sasanos to adopt Masayuki.
Shinji: Masayuki is the first son! It's far more natural that the second son being adopted.
Grandmother: We will tell you why when you've grown up. Did Masakuki tell you anything?
Shinji: Nothing particulary, except that there's a piano in our house.
That evening, Shinji hears Grandmother and his parents talking. They say Aunt Kyouko commit suicide. Grandmother says Shinji mustn't have remembered the piano because it was hidden immediately after Kyouko died. Shinji is scared. He wonders why the piano was hidden, why Aunt Kyouko commit suicide. Then he hears the sound of piano. He looks back and sees a woman playing the piano.
The next morning, Grandmother tells him she has something to tell him.
Shinji: Masayuki is going to play the piano at a competition.
Grandmother: Does he play the piano?
Masayuki wonders if he saw a woman playing the piano in the dream. Masayuki seems to have a lot of pain in his arm. He says he remembers crying because he didn't want to be adopted by the Sasanos.
Masayuki:You said you would be an adopted child because I was crying. I said to you "Really?", but Mother came to take me soon after that.
Shinji: No, it was me that was crying. You said you would be an adopted child.
Masayuki: No, it was me that was crying. It was decided that I was to be adopted.
Shinji wonders when his memory changed. In his memory, the same face as his has been crying.
Mr. Andou finds out that Shinji has played the piano instead of Masayuki at the final competition. Shinji and Masayuki escape from the theatre and go to the city hall to see Shinji's family registry. Shinji thinks he might be the first son. The family registry says Shinji is the first son, and he is an adopted child.

Mr. Andou visits Shinji's house. He tells Shinji's grandmother and parents that Shinji played the piano at the competion instead of Masayuki.
Grandmother: That's absurd! He can't play the piano.
Andou: Don't you know that I've taught him how to play for two years? He has progressed remarkably fast. He says he has a friend who is an excellent pianist and he can learn how to play if he sees the friend playing the piano. The friend must be Masayuki.
Grandmother goes into the room with a big window and finds Shinji and Masayuki there.
Shinji shows her a photo. A young woman with a bouquet of lilies and Grandmother are smiling in front of a grand piano in the photo.
Shinji: Grandmother, am I Shinji or Masayuki? Who is the woman in the photo?
Grandmother: This is Kyouko. She is your mother. She was a pianist. She fell in a slump and got sick. She commit suicide when you were one year old.
Grandmother asks Mr. Andou and Shinji's parents to move some furniture. A piano appears in a closet. Grandmother says Kyouko practiced with the piano when she was a child. Grandmother begins to play the piano. Masayuki says to Shinji "There's someone near the piano." Shinji sees someone standing behind Grandmother.
Grandmother starts telling to them. She was a piano teacher. She was very eager to make Kyouko a famous pianist. Kyouko thought she was worthless if she wasn't a pianist. Even though she married Mr. Sasano, she wasn't a good wife. She came back to her mother's house to give birth to Masayuki and Shinji, and she never went back to her husband's place. She had a trouble with her fingers and got neurotic. She ended up taking sleeping pills to kill herself. Grandmother thought it was her fault that Kyouko bacame such a person. She dicided she wouldn't involve in anything related to piano. Her son and his wife had no children, so they adopted Shinji as their son, and gave Masayuki back to Mr. Sasano.
Grandmother tells Shinji to play Kyouko's piano from now on.
Mr. Sasano is a piano tuner. He is going to visit Shinji's house to tune Kyouko's piano. Masayuki says "Father said our late mother said she would make her kids learn how to play the piano."