Kang Mu-jin conquered the ‘Yeon-gi-gye’ (Realm of Connected Qi), a world where the sun and moon coexist, and rose to the position of the strongest under the heavens.

After mastering the "Immortal Diamond Qi Art" a technique that makes him impervious to any attack, he finally returns to his original world.

“The Diamond Escort Agency is ruined.”
“Ru—Ruined?!”

He finally made it back home, but... his home has gone completely bankrupt?!