Yujin and Minjoo have been friends since they were little. Ever since then they always go to the rooftop after sunset to see the stars.  An innocent friendship that turns into a romantic attraction. Will you be willing to take a risk? (Story based on 'Rooftop' by N.Flying)

In the new era, thought itself will be transmitted through radio waves. After a series of natural disasters, the world's oceans have risen and swallowed entire cities. Inland cities begin to have coastal climates, and many people are displaced. Country development is at a standstill. An Yu-jin is a young college student who regularly writes to her gentle android, Kim Min-ju. She teaches her an emotional warmth that is common among all of the machinery of the universe.

She was able to keep a hundred promises, but she broke the four most important vows. Will she be willing to give everything up to keep one last promise she made?

People say love is all about spring, the butterflies in your stomach, the colorful rainbow, and the dancing of lovely flowers. But things could go wrong too, because not every love story has its own happy endings.  The butterflies will die, the rainbow will disappear and the flowers will wither.