For anyone wondering about the meaning of the MV, Hoyeon is Cupid, or at least one of the Cupids assigned the task of making people fall in love (which can be inferred from the first few scenes of Side A where she follows people around and makes them kiss/hold hands). However, she doesn't seem to enjoy her life and work very much. Then, at the exhibition, she sees and gets curious about this painting of Cupid & Psyche (Cupid's human wife) and this guy admiring it. For some (brief) context, according to Roman mythology, Cupid fell in love with Psyche, a human that his mother disliked, and then married her although it was forbidden. Hoyeon follows the guy and falls in love with him, but he cannot see her since she is Cupid. So one night, she strips herself of her Cupid responsibilities to be in her human form and meet the guy. They date and have a great time for a while, until Tony Leung, who I suppose is one of the 'managers' or higher-tiered gods, finds out. He shows up, clears the guy's memory of Hoyeon, and makes her invisible to him once again. What's even worse is, he seems to make the guy fall in love with the woman walking behind Hoyeon at the same time. So in the end, Hoyeon has to accept her fate as a Cupid, who, despite her desires to love and be loved, has to spend eternity alone. Update: Since some of you also asked about NJ's role in the MV, here's my guess! Based on (1) their outfits, (2) their ability to be on the rooftop at midnight watching Hoyeon (very dangerous xD), (3) their ability to see Hoyeon, I would say they are goddesses/semi-goddesses/muses who serves as Tony's eyes and ears on Earth. We can see that they have their human form during the day with regular jobs, but at night (sometimes during the day also) they would wear similar mythical-looking dresses and accessories dancing in museums(?) or watching Hoyeon, so we can safely assume that they are not human but live a human life while doing their real job, so a type of secret surveilling agent of sort. They are most likely the ones who reported Hoyeon's 'wrongdoings' to Tony :D