The film draws inspiration from the life of Hyakken Uchida, a notable Japanese academic and author (1889–1971). Set in the tumultuous period preceding the Second World War, Uchida, portrayed as a dedicated professor of German, delivers an emotional farewell to his disheartened students as he announces his retirement. In 1943, he relocates to a larger home, though his wife harbors worries about their neighborhood's safety. Two of his students, with mischievous intent, stage a break-in, only to stumble upon Uchida's handwritten guidelines for burgling their own house.
He later invites several students to a dinner, but due to wartime rationing, he feels embarrassed that he can only offer them venison and horse meat. Tragedy strikes when his home is consumed by flames in U.S. bombing raids, forcing Uchida and his wife to seek refuge in a cramped shack, deprived of basic amenities save for their remaining belongings.
As peace returns after the war, Uchida's former students band together to throw a celebratory banquet in his honor. When inquired about his readiness to leave this world, he firmly responds, > "Not yet," which gives rise to the banquet receiving the whimsical title of the “Not Yet Banquet.” As the lively festivities wind down, two American military policemen appear yet are disarmed by the joy resonating in the room.
With the dedication of his students, Uchida builds a new house for him and his wife, complete with a serene pond that holds a tiny island at its center. During this time, they are visited by a stray alley cat, which Uchida lovingly names Alley. However, trouble looms as a developer purchases the lot across from their home, insisting he must buy their place as well. Uchida's refusal leads to the realization that the development would obstruct his view. Thankfully, his students unite to buy the contested lot, returning it to the seller who finds themselves in need of both money and the land, promising not to encroach on Uchida's view.
As fate would have it, Alley goes missing during a storm, plunging Uchida into a profound sorrow. He exhaustively searches for the cat, rallying support from his students, local schools, and townspeople, but false leads only deepen his despair. A brief moment of hope arises on a train when he believes he glimpses Alley at a station, yet the train pulls away without a reunion.
Soon after, a new feline companion appears. He names this one Kurz, translating to "short" in German, and this new presence brings a spark of happiness back into his life, lifting his previous despondency.
As the tradition continues, his former students hold the seventeenth Not Yet Banquet. This time the gathering reflects a new generation, as the children of his students present him with beautiful flowers while grandchildren surprise him with a sizable cake. After thanking everyone and sharing some heartfelt words, Uchida tragically collapses from arrhythmia. He is brought home to rest, where he falls into a deep slumber, dreaming of his childhood and the delightful game of Hide-and-seek. In his dream, while seeking a hiding spot, he hears children urging him, inquiring if he is ready, to which he replies, "not yet." Ultimately, he discovers a perfect hiding place while gazing out at a golden sun.
This poignant narrative melds actual events from Uchida's life, like the relentless search for his missing cat and the struggles following the loss of his home, with Akira Kurosawa's reflections on Japan's modern history, including the American occupation, which he previously approached with more subtlety in his earlier films.
