Mosaic (Wong Cho Lam), an urban sketcher suffering from ALS, reunites with Angelfish (Charlene Choi), a bank teller and his old primary school classmate, at a school function. When his condition worsens, Mosaic asks Angelfish to fulfill his one last wish: To be his girlfriend for just one day. Over the course of the day, Angelfish's appreciation of this city and of life is reignited.