Guarding the increasingly dilapidated mountain gate, Chen Yan is jolted when an old plaque suddenly crashes down, making him realize for the first time that securing the place matters far more than maintaining a facade. With the help of Liu Qinghe and Wei Boan, he transitions from fixing pillars, checking drainage, and organizing storehouses to recording hazards and arranging receptions, gradually learning to prioritize tasks and handle miscellaneous duties practically. A month later, the old mountain gate reopens stably, and he transforms from a mere laborer into a gatekeeper who understands maintenance, management, and how to keep the rules alive.