Kim Myungsoo was Lee Sungyeol's best friend. Lee Haena was Lee Sungyeol's best friend. so with that Myungsoo and Haena became a bestfriend. Lee Sungyeol loved Haena, she was his first love but she never knew and Sungyeol never said to her. But Haena liked Myungsoo so did He. So Haena and Myungsoo were dating. But someday, Haena pregnant and the baby was Myungsoo's but he didn't want to take the responsibility so he ran away. Lee Haea had nothing but Sungyeol.   

Upon first meeting this person, there’s a sweet beginning, but once you come to really know each other and grow comfortable, you suddenly realize that the relationship no longer brings any particular value to your life and is perhaps, even detrimental.  Sometimes, we hold on to people purely based on how long we have known them. Time can tie people together, but if you feel as though there’s nothing substantial keeping you connected, time is not a strong enough reason to

Because they were mean to be