In response, China dispatches Longjing (Dragon Whale), a cutting-edge nuclear submarine, to dive deep into the ocean while assigning the Jiaolong Squad to investigate the wreckage of the enemy's sunken submarine. However, as navy officials and soldiers descend into the depths, they find themselves entangled in a perilous underwater battlefield teeming with unforeseen dangers and hidden threats.

Yu Dong, the film's chief producer and president of Bona Film Group, shares that the movie has fulfilled his decades-long dream of making a film about the rise of China's naval forces.

As a child, he came across The Naval Battle of 1894, a classic film depicting the First Sino-Japanese War (1894-95). Watching Deng Shichang, an admiral of the Qing Dynasty's (1644-1911) Imperial Chinese Navy, steer the Zhiyuan cruiser in a heroic yet tragic attempt to sacrifice himself in trying to ram and sink the Japanese flagship Yoshino, Yu was moved to tears.