S1, E4: To protect Do-ha, Sol-hee pretends to be his girlfriend. They finally get to know each other’s real names, but Sol-hee begins to doubt Do-ha's honesty. Oddly, her lie-detecting ability doesn’t react to him, so Sol-hee begins to wonder if her ability doesn't work for Do-ha. She tries to induce him to tell a lie, and suddenly, an urgent phone call comes in from someone looking for Do-ha.