In the fifth year of Xianqing (660 AD), General Su Dingfang returned from his campaign that had crushed Baekje, leaving Liu Rengui behind to hold the garrison with little more than the shattered remnants of the Tang fleet. Half a world away, Japan mobilized its entire national strength, proclaiming that "what concerns Baekje concerns Yamato," and worked day and night in Tsukushi Bay to construct six hundred warships for a decisive push northward. Pei Xingjian, a staff officer from Yangzhou, is struck down by a Japanese sniper's arrow—and awakens in this era with a mind full of shipbuilding knowledge centuries ahead of its time. No watertight bulkheads? No lateen rigs for sailing against the wind? No standardized dry docks? He commits himself to rebuilding Tang naval engineering from scratch, and a three-year countdown begins. When the Japanese armada floods into the Baekgang estuary in overwhelming numbers, they will find themselves facing not only Liu Rengui's steely command but also an iron tide of vessels forged by Pei Xingjian—a fleet a full generation beyond anything the age has seen. Four against four hundred. This single engagement will decide the fate of East Asia for the next thousand years. (Hardcore historical military fiction, meticulously researched, and no mindless power fantasy.)