Arpeggio of Blue Steel

The I-401 and her intrepid crew, captained by Chihaya Gunzo, have escaped the trap set for them by the Fleet of Fog outside their home port of Yokosuka. Successfully returning home after two years away should be a triumphant occasion, but there are those who think otherwise. In fact, if they have their way, they will take the I-401--along with her mental model, Iona--away from Gunzo entirely and bring her back under government control. Human politicians...

The Fog battleships Haruna and Kirishima have been destroyed through the combined efforts of the I-401 and the Japanese government's "White Whale" sub, and the port of Yokosuka is safe -- but the same can't be said for the I-401. While still damaged from the battle, the 401 comes face to face with a Fog submarine that Iona doesn't recognize, and it's not exactly friendly! Back on land, Haruna, the mental model of the destroyed ship, is found by Osakabe...

"In the early 21st century, the majority of Earth's landmass is submerged due to rising sea levels. Enter the Fleet of Fog, a host of sentient alien battleships of unknown origin who easily decimate earth's naval forces. Humanity is now on the verge of extinction. In the year 2039, the stalwart Captain Chihaya Gunzou and his intrepid crew on the Blue Steel fleet may be humanity's last chance to fight off the alien invaders. The Blue Steel fleet happens...

"All hands on deck. In the fight against the Kongo, Iona s mustering all the strength she can get including Ashigara and Haguro, who are now stuck aboard the 401. With the Kongo on the hunt and nowhere else for them to go, the mental models have no choice but to lend their enemies a helping hand. The end of the battle between Kongou s hunting fleet and the 1-401 draws nigh!"-- cover page 4.

"Gunzou might still be missing in action, but Iona is determined to make sure that his plan to smuggle a warhead across the Pacific Ocean goes ahead. If it's successful, it will give humanity a much needed win against the Fog. But in order for the plan to work, the I-401 will have to act as a decoy and go toe-to-toe against a dangerous enemy."-- cover page 4.