Chen Ye, heir to a century-old shipbuilding and repair family, is burdened with enormous debts when his ancestral shipyard unexpectedly opens a space-time passage to an ancient feudal domain. Xiao Ce, the prince responsible for defending the domain, is struggling with outdated warship technology as river pirates and imperial armies repeatedly invade, leaving the people suffering. Using modern ship repair techniques, industrial equipment, and other technological resources, Chen Ye provides assistance across time and space, repairing warships, constructing harbor defenses, and developing overseas trade and civilian industries. The two establish a cross-temporal partnership with a 30-70 profit-sharing arrangement. Chen Ye clears his debts, establishes a shipbuilding company, and rises to wealth, while Xiao Ce uses modern technology to secure his domain and bring prosperity to its people. Eventually, they establish lasting trade relations and continue working together, with Chen Ye ultimately revered by the people of the ancient world as the Divine Craftsman Who Protects the Nation.