Kouhei Araki, a veteran editor in the dictionary editorial division at Genbu Publishing, intends to retire to provide better care for his ailing wife. However, prior to his retirement, he must secure a replacement to finish his latest project: a new dictionary titled The Great Passage. Despite his efforts, he fails to find anyone suitable, as compiling a dictionary demands considerable patience, time, and dedication. Mitsuya Majime works in Genbu Publishing's sales division, yet he possesses poor social skills and struggles to read the mood in most situations. Nevertheless, he demonstrates enthusiasm for words, driven by his love of reading and careful nature. These qualities attract Araki, prompting him to offer Majime a position in the dictionary editorial department. Upon accepting the role, Majime feels uncertain about his abilities and questions whether he will fit in with his new colleagues. Yet, amidst the vast sea of words, The Great Passage will bring them together.