Set in the island Kinmen, often seen as the most dangerous military base because it is geographically close to China, Paradise In Service follows the adventure of a boy who serves his military service in Unit 831 from 1969 to 1972, in preparation for a war that could erupt anytime. Through an unlucky lottery draw result, Pao, a twenty-something young man from Southern Taiwan has to serve the military in the remote and perilous Kinmen. Moreover, he is assigned to the Sea Dragon (ARB), a unit known for the toughest physical training. It never occurs to Pao that the greatest challenge is not his military training but a special task he is later appointed to. In this peculiar assignment, Pao vows to keep his virginity against all odds.