The Great Passage follows Kouhei Araki, a veteran editor in the dictionary editorial division at Genbu Publishing, as he prepares to retire so he can care for his ailing wife. Before he leaves, he is determined to finish one final project: a new dictionary called The Great Passage. Finding someone capable of taking over is far from easy, because making a dictionary requires patience, time, and total dedication.
His search leads him to Mitsuya Majime, a quiet employee in Genbu Publishing's sales division who struggles with social skills and often fails to read the mood in most situations. Even so, Majime has a sincere enthusiasm for words, shaped by his love of reading and his careful, meticulous nature. Araki recognizes that potential and offers him a position in the dictionary editorial department. As Majime accepts the role, he is unsure of his abilities and whether he will fit in with his new co-workers. Yet amid the vast sea of words, The Great Passage brings them together through their shared commitment to language.