Lewis, an adventurer in his late twenties, has been training hard for many years, but he remains the weakest E-rank. He is mocked and scorned by those around him.One day, the imperial capital is attacked by monsters, and Lewis and his partner Alicia head out to deal with the situation.Lewis barely manages to defeat one monster, and is granted his long-desired level-up, but at the same time, he obtains a mysterious skill called "Unconditional Victory."This skill holds incredible power. Lewis is stunned as he takes down the monsters in an instant.With this skill, he might be able to become like Elgar, the legendary hero he admired as a child...The heroic tale of the strongest old man, who knows the pain of unrequited suffering and the pain of the weak, has begun...!