Aiming to protect Raphtalia from the assassins of Q'ten Lo, Naofumi Iwatani travels with his friends to the eastern isolationist kingdom. On his way, Naofumi stops over in Siltvelt, a kingdom built by a former shield hero, where he is revered as a god and is offered a chance to rule the country.

Naofumi is unwilling to accept the position, preferring to continue his journey before the next wave of monsters threatens to destroy the world. Nevertheless, he finds himself embroiled in local political feuds. After he escapes from an assassination attempt, Naofumi decides to confront the leaders of Siltvelt, and this time, he is determined to show that old grudges and petty ambitions are nothing compared to his resolve to save the world.