In 2039, fleets of powerful sentient warships, armed with advanced technology and possibly 'alien' weaponry, mysteriously appear and devastate the world's naval forces.

These ships, collectively known as 'The Fleet of Fog', impose a worldwide naval and aerial blockade, preventing humanity from both traveling the oceans and to other nations.

In 2056, 17 years after the blockade began, Gunzō Chihaya, a former student of the Japanese National Marine Academy, is the captain of a small group of privateers called the 'Blue Steel'.

Due to I-401's technology and Gunzō's tactical skills, the Blue Steel have not only survived several encounters with the Fleet of Fog but managed to sink one of their most powerful warships.

Gunzō and his crew are hired by a faction of the Japanese government to deliver the prototype of the vibration warhead, a powerful weapon that may finally allow mankind to fight back against the Fog, to the United States.

[5][6] A spin-off manga illustrated by TALI titled Salty Road which focuses on Takao, I-402, and Zuikaku during their infiltration of Yokosuka, began serialization on October 16, 2014, in Young King OURs magazine.

[7] A CG rendered anime produced by Sanzigen titled Arpeggio of Blue Steel -Ars Nova-, began airing on October 7, 2013.

[45] In September 2013, it was announced that there would be a collaborative project between the Arpeggio of Blue Steel anime and the online game Kantai Collection.

[46] Illustrators for Kadokawa Games, including Shibafu and Konishi, are responsible for drawing some of the end cards, which feature crossovers with Kantai Collection characters.