Although Jirou Horikoshi's nearsightedness prevents him from ever becoming a pilot, he leaves his hometown to study aeronautical engineering at Tokyo Imperial University for one simple purpose: to design and build planes just like his hero, Italian aircraft pioneer Giovanni Battista Caproni. His arrival in the capital coincides with the Great Kanto Earthquake of 1923, during which he saves a maid serving the family of a young girl named Naoko Satomi; this disastrous event marks the beginning of over two decades of social unrest and malaise leading up to Japan's eventual surrender in World War II. For Jirou, the years leading up to the production of his infamous Mitsubishi A6M Zero fighter aircraft will test every fiber of his being. His many travels and life experiences only urge him onward⁠—even as he realizes both the role of his creations in the war and the harsh realities of his personal life. As time marches on, he must confront an impossible question: at what cost does he chase his beautiful dream?

At the turn of the millennium, Ginei Studio's dilapidated buildings are set to be demolished. Ex-employee and filmmaker Genya Tachibana decides to honor this occasion with a commemorative documentary about the company's star actress: Chiyoko Fujiwara, the reclusive sweetheart of Shouwa Era cinema. Having finally obtained permission to interview the retired starlet, an enamored Genya drags along cynical cameraman Kyouji Ida to meet her, ready to put his lifelong idol back in the spotlight once more. Hidden in this secluded mountain retreat is a thousand years of history condensed into one lifetime, waiting to be narrated. Chiyoko's recollections take them on an illusionary journey through Japanese cinematic history that transcends the boundaries of reality; the saga of her acting career intertwines with her filmography, the actors in her life blend seamlessly with the characters on screen, and the present melds with the past. Though the actress may have retired at the height of her career 30 years ago, the curtain on her life's stage has yet to fall.

Taeko Okajima is a 27-year-old, independent woman who spent her entire life in Tokyo. Looking to unwind from the rush of the big city, she decides to visit her family in the country to help out during the harvest. On the train there, Taeko vividly recalls her memories as a schoolgirl in the initial stages of puberty, as if she is on a trip with her childhood self. A young farmer named Toshio picks her up at the station, and they quickly develop a friendship. During her stay, Taeko forms strong bonds with family and friends, learning the contrasts between urban and rural life, as well as the struggles and joys of farming. Nostalgic and bittersweet, Omoide Poroporo takes on Taeko's journey as an adult woman coming to terms with her childhood dreams compared to the person she is today.

The time: 1814. The place: Edo, now known as Tokyo. One of the highest populated cities in the world, teeming with peasants, samurai, townsmen, merchants, nobles, artists, courtesans, and perhaps even supernatural things. A much accomplished artist of his time and now in his mid-fifties, Tetsuzo can boast clients from all over Japan, and tirelessly works in the garbage-loaded chaos of his house-atelier. He spends his days creating astounding pieces of art, from a giant-size Bodhidharma portrayed on a 180 square meter-wide sheet of paper, to a pair of sparrows painted on a tiny rice grain. Short-tempered, utterly sarcastic, with no passion for sake or money, he would charge a fortune for any job he is not really interested in. Third of Tetsuzo's four daughters and born out of his second marriage, outspoken 23-year-old O-Ei has inherited her father's talent and stubbornness, and very often she would paint instead of him, though uncredited. Her art is so powerful that sometimes leads to trouble. We're father and daughter; with two brushes and four chopsticks, I guess we can always manage, in a way or another. Decades later, Europe was going to discover the immense talent of Tetsuzo. He was to become best known by one of his many names: Katsushika Hokusai. He would mesmerize Renoir and van Gogh, Monet and Klimt. However, very few today are even aware of the woman who assisted him all his life, and greatly contributed to his art while remaining uncredited. This is the untold story of O-Ei, Master Hokusai's daughter: a lively portrayal of a free-spirited woman overshadowed by her larger-than-life father, unfolding through the changing seasons. (Source: Production I.G)