The series follows the story of the long-term guests at Paradise Inn, located in the heart of Seoul. From the first room to the sixth room, all the guests are different in age, gender, and even where they grew up.

An old stately inn stands in the heart of Seoul. It may be old, discolored, and weathered, but Nakwon Inn exudes old-world charms. As the typical cold uneventful winter comes to an end at the inn, guests start to arrive one by one as if each had promised to be present. Strangely and coincidentally, each one of them repeats Never Twice as they enter. The truth is, they all have a fateful reason to be there. What could have brought these individuals together? And what do they all have in common considering their long-term stay, assigned room numbers, gender, age, and hometown? The real reason for coming to Nakwon Inn unfolds.