Arman Bruno, recently recruited as a trainee for the Aseatic Defense Division, is one of a handful of survivors from a devastating attack aboard the West Sea Citadel known as the Buhawi. Bleeding in his arms is the Fleet Admiral Amihan, the hero of the West Sea War, who reveals to him that someone inside the government was working against the New Republic.

With the help of his fellow recruits Marcus and Dara, along with his training officer Andreus, they go back to the mainland to find the city in chaos; The Crimson Legion was running rampant in the Metro. It is now up to them and their Amanium-powered submersibles to devise a plan to save the city, reveal the traitor, and hopefully make it out alive.