Anime adaptation of the stage play Touken Ranbu: Kyoden Moyuru Honnouji.

Sequel of Touken Ranbu: Hanamaru.

The war between the Terrans and the Vers Empire of Mars has ended, allowing humanity to blissfully enjoy their lives in a time of peace. Nineteen months later, however, the Vers princess makes a shocking public declaration: the Terrans are a foolish race that covets resources, destroys nature, and are devoted to the pursuit of pleasure. And so, to protect their precious Earth, she calls upon her knights to take up arms, and the raging battle between the two civilizations reignites. Slaine Troyard has found a place among the Martians, giving Earth a short respite from the war against the Vers Empire. However, a peaceful resolution seems inconceivable. The various people who fought desperately for survival in the past now find themselves in the midst of yet another bloody and chaotic conflict, one that will forever alter the fate of humankind.

When the Sirens, an alien force with an arsenal far surpassing the limits of current technology, suddenly appeared, a divided humanity stood in complete solidarity for the first time. Four countries—Eagle Union, Royal Navy, Sakura Empire, and Iron Blood—formed Azur Lane, paving the way for the improvement of modern warfare, which led to an initial victory against the common threat. However, this tenuous union was threatened by opposing ideals, dividing the alliance into two. Sakura Empire and Iron Blood broke away and formed the Red Axis, and humanity became fragmented once again. As a seasoned and experienced fighter, the Grey Ghost Enterprise shoulders Azur Lane's hope for ending the war. But behind her stoic persona hides a frail girl, afraid of the ocean. Even so, she continues to fight as she believes that it's the only purpose for her existence. Meanwhile, Javelin, Laffey, and Unicorn—three ships from the union—stumble upon Ayanami, a spy from the Red Axis. Strange as it may seem, they try to befriend her, but as enemies, their efforts are for naught. Still, they persevere in hopes of succeeding one day. Amidst the neverending conflict within humankind, the keys that could unite a fragmented race might exist: a soldier coming to terms with her mysterious personality and camaraderie between those with different ideals.