Su Yan, a homebody, accidentally clicks an online ad and finds himself in Linyuan, the capital of the demon world, where he unexpectedly becomes a demon king despite knowing nothing about magic. To avoid being exposed as a powerless pushover, he befriends the powerful General Hua, who is also a time traveler from the modern world. Together, they navigate Linyuan, leveling up and battling monsters while hiding their true identities. They tame the Silver Dragon as their mount and outsmart high-ranking officials. During the rare Dengming Assembly, they facilitate peace talks between the monster clan's Young Master Ying Ri and the immortal realm's Lord Lu Zhen. They also seek a magical bead to restore Su Yan's rebellious younger brother Yu Ke's primordial spirit. When the bead goes missing, chaos erupts in Linyuan City, threatening the demon world and forcing Su Yan into a crucial decision as the Demon King.