Carpe Diem revolves around the story of the main character, Jung, and his time spent with a girl named Ai. The game's plot is centered around the question of what makes someone perfect.

Throughout the game, players will experience a short, yet bittersweet story, where they will have a day to enjoy a date and see the world from Jung's perspective. The game is a visual (kinetic) novel, aimed at showing the importance of setting the right priorities in life. It is intended to be a single playthrough kind of novel, with choices leading to the same ending, but taking different routes.