Kantai Collection is a Japanese free-to-play web browser game. The gameplay is centered upon building squadrons composed of individual characters represented as cards with different attributes, and then sending said squadrons out on missions. Each of the characters are moe anthropomorphisms of World War II naval warships which are depicted as cute girls, known as "Fleet girls". These personified warships are based on real-life vessels which are explained in detail within the game; the physical characteristics, appearances and personalities of each of the girls correlate in some way to the real-life vessel (for example, ships with a larger displacement tonnage are usually depicted as older girls with more mature bodies, while smaller ships have petite and underdeveloped figures, with a few exceptions). The player takes on the role of an admiral and organizes their fleets in battle in order to win. Combat is largely automated, and manual actions by the player include micromanagement such as building and repairing.

The "shipgirls" are girls who carry in their bodies the souls of the naval vessels of the past.

They are the only ones who can stand up to the "deep-sea dwellers," a group of hostile vessels born from the bottom of the sea, and they are in the battle to protect the people and the sea.

However, they were either wounded or killed in the face of the overwhelmingly massive deep-water fleet, and the tide of the war was swinging sharply.

In the midst of all this, the destroyer "Shigure" was assigned to a new fleet.

The new fleet to which she is assigned is the "First Ranger Unit" and its "Third Unit" (1YB3H). However, the fleet was a "mish-mash" of the old battleships "Yamashiro" and " Fusou," which had been deployed in the rear, and the only other ship, the aircraft cruiser "Mogami," as well as four destroyers.

As part of a mission to regain their lives by using all their remaining strength, Shigure and the other 1YB3Hs set sail for the doomed straits on a decoy-like mission to cover the main force.