63-year-old Jong-chil has been re-employed as a senior water purifier engineer after retiring from public service, and is working as a trainee.
 While under pressure for sales profits, his co-worker Hyun-suk informs Jong-chil of his business secret-selling a new water purifier under the pretext of repair to a customer, and making a profit by selling the customer’s used water purifier. But Jong-chil doesn't want to do the job.