When an otherworldly threat in the form of the powerful 'Sirens' emerges, humanity, previously divided, unites for the first time. This newfound alliance, Azur Lane, comprising Eagle Union, Royal Navy, Sakura Empire, and Iron Blood, leverages advanced technology to secure an initial victory. Yet, internal discord fractures the unity as Sakura Empire and Iron Blood defect to create the Red Axis. Amidst this turmoil, the renowned fighter 'Grey Ghost' Enterprise embodies Azur Lane's hope, concealing her vulnerability and fear of the sea behind a strong facade. Simultaneously, three ships—Javelin, Laffey, and Unicorn—encounter Ayanami, a Red Axis spy. Despite their attempts at friendship, their conflicting allegiances thwart their efforts. Undeterred, they persist in their quest for harmony. As humanity grapples with its divisions, the path to unity may lie in a soldier confronting her enigmatic past and the bonds forged between ideological rivals.