"I guess I thought if I ever made it back here, we could go on adventures, just like we used to. But it's been ten years. We've all changed, in more ways than one. From this moment on, this is the first step in the life of rookie adventurer Lock!"

With no other options, Luck makes the choice to hold the line against the unending demonic hordes alone, to make sure his comrades can escape with their lives. However, through a combination of fortune, skill, and ingenuity, he holds that line for ten straight years, eventually coming out on top singlehandedly. Now he has to tackle the dilemma of how to occupy himself in a world where he holds a myriad of roles: that of a legend, that of a veteran, and that of a brand new face.

[Source: manga version summary via Comikey]