Arpeggio of Blue Steel

The Fortress Port of Yokosuka

The I-401 and her crew reach the Yokosuka Base for repairs and resupply, and Gunzō takes Iona for a visit to Navy memorial for those that died in the war against the Fleet of Fog. Soon after, they are taken against their will by the Japanese Army with the rest of the crew to meet Ryōkan Kita, a former member of the Navy and an influential politician who attempts to convince Gunzō to relinquish the I-401 to the Japanese Army with no success. Meanwhile, Takao is approached by the mental models of Fog surveillance submarines I-400 and I-402 and reveals her intentions to abandon the fleet and join Gunzō's side. However, she is informed by them that two Fog battleships were dispatched to sink the I-401 and Takao leaves, claiming that she will wait for Gunzō at another location. When the Yokosuka port is under attack by said battleships, Haruna and Kirishima, Gunzō and his crew return to their submarine, subduing all resistance from Kita and his men and prepare themselves to confront the new enemies before them.