Ep. 4: I-401 Evades Yokosuka Assault by Kirishima and Haruna
Aired on October 29, 2013

Fast battleships Kirishima and Haruna launch an assault on Yokosuka. I-401 deploys to intercept them within the defensive barrier, employing diverse strategic tactics to counter their overwhelming firepower. Observing the tactical evolution humans have introduced to I-401, Kirishima and Haruna resolve to eliminate the submarine with a full-scale attack. Despite the intense pressure and the enemy's determination to destroy her, Gunzou retains a hidden advantage that may turn the tide of this critical engagement against the superior naval forces.
Episodes
- Ep. 1 · Rising seas and the Fleet of Fog dominate the high seas in the mid-21st century
- Ep. 2 · Gunzou faces Takao while navigating toward Yokosuka with his new command
- Ep. 3 · I-401 arrives at Yokosuka to retrieve a secret warhead amid political pressure and sudden attacks
- Ep. 4 · I-401 Evades Yokosuka Assault by Kirishima and Haruna
- Ep. 5 · Haruna and Kirishima investigate Makie Osakabe and the Vibration Warhead at Iwo Jima
- Ep. 6 · Haruna protects Makie with Kirishima's aid while Iona arrives and Takao awakens.
- Ep. 7 · The I-401 crew reaches Iwo Jima base where Hyuga and Takao await their return
- Ep. 8 · Hyuga negotiates with Kongou's decoy while Gunzou prepares to deliver a vibration torpedo to the United States.