Akira Kaido (Osamu Mukai) berasal dari latar belakang kaya. Ayahnya mengelola sebuah perusahaan besar. Akira Yamazaki (Takumi Saito) berasal dari latar belakang sulit. Ayahnya bangkrut dan keluarga mereka melarikan diri pada tengah malam. Akira Kaido dan Akira Yamazaki dipekerjakan di bank yang sama.
April 1986, pelatihan untuk karyawan bank baru berlangsung. Dua tim dibuat untuk menjalankan misi. Akira Kaido dan Akira Yamazaki memimpin tim lawan.
Yuki Hase (Kento Yamazaki) Seorang Siswa SMA ingin dekat dengan teman sekelasnya Kaori Fujimiya (Haruna Kawaguchi) yang sendirian. Kaori Fujimiya menolak untuk dekat dengan Yuki Hase, karena dia melupakan teman-temannya setiap hari Senin. Meski Kaori mengatakan pada Yuki alasan dia tidak mau berteman, Yuki tetap ingin mendekatinya.
Kasumi (Erina Mano) gets a job as a teacher at an elementary school. This fulfills a lifelong dream for her, but Kasumi is too passionate with her job. She overworks herself and gets burned out from her job. Kasumi quits her teaching job. She is still only 28 years old. Kasumi needs to find work and begins to take short-term jobs. She meets mysterious employee Masakado (Atsuko Asano) of Hello Work.
Jun Jonochi (Mirei Kiritani) works at a paper manufacturing company. She is earnest, but clueless about her own appearance. She doesn't have any interest in making herself look good. One day, she realizes that people don't view her as other women. She begins to read up on things like make-up and fashion trends with her two female colleagues.
Takuto Hirabayashi (Arata Horii) lives with his two friends Kyohei Hano (Yuki Yamada) and Hajime Okayama (Ryo Mitsuya) at a share house. They have been friends since high school. Takuto Hirabayashi now works at a company, Kyohei Hano works at a trading company and Hajime works for an apparel brand.
30-year-old Rinko Kamata (Yuriko Yoshitaka) works as an unpopular screenwriter. She doesn't have a boyfriend, but she has two female friends Kaori and Koyuki. They meet regularly at a bar. There, they complain about their situations and go through what if scenarios. One day, Rinko Kamata decides to go for happiness at love and work.
Set along the Shimanto River in Kochi Prefecture, Japan. "Osozaki no Himawari" depicts the lives of seven people who follow vague dreams, but live an ordinary life.
Jotaro Kodaira (Toma Ikuta) is about to turn 30-years-old. Jotaro has recently been laid off from work and around the same time his girlfriend of seven years dumps him. Jotaro then spots a website recruiting people for work in Koichi Prefecture in a regional revival cooperation.
Kahori Nikaido (Yoko Maki) is clinician sent to work in her hometown of Koichi Prefecture. On the way to there, Kahori meets Jotaro Kodaira.
A postman learns that he doesn't have much time left to live due to a terminal illness. A devil then appears in front of him and offers to extend his life if he picks something in the world that will disappear. The man thinks about his relationships with ex-friends, ex-lovers, relatives and colleagues who will be sincerely sad when he dies.
Naho Takamiya (Tao Tsuchiya) is a 2nd year high school student. During the spring, Naho Takamiya receives a letter sent by herself from 10 years in the future. In the letter, she liked transfer student Kakeru Naruse (Kento Yamazaki). Kakeru Naruse carried emotional scars from his mother's suicide and he died one year later. 26-years-old Naho Takamiya thinks about Kakeru Naruse often.
2nd year high school student Naho Takamiya, with the knowledge of what she feels 10 years in the future, takes action to change her future.
Moritaka Mashiro (Takeru Satoh) doesn't want to follow in the path of his uncle who worked as a manga artist, but ultimately died because of exhaustion. Moritaka Mashiro figures he will graduate from school and work at an office. Things change though when falls in love with a girl at school. The girl, who hopes to become a voice actress, tells Moritaka they can marry, but only after they both achieve their dreams. Moritaka then teams up with fellow classmate Akito Takagi (Ryunosuke Kamiki) to publish their first manga.