The Unbroken is based on a novel by Toyoko Yamasaki which centers on Hajime Onchi, an employee of "NAL," a large national airline. The first part of the novel focuses on Onchi's activity as the chairman of the employees' union in the 1960s; his reward for fighting for better working conditions for the staff is a series of postings abroad, to Pakistan, Iran, and finally Kenya, a destination to which the company does not even fly. The second and third parts of the novel take place in 1985 and chronicle the crash of a jumbo jet and its aftermath within the company.