your mom yoon young got accidentally travelled to past by hae Jun your dad and he is a time traveller of 2024 and died in 2025 so he travelled to 1987 where the cause happened and yoon young dad name is Hee-sub who never cares about his wife nor yoon young but cares about his older brother yu-sub and her mom name is soon-ae and yoon young and hae-jun got romantic things and everything and at they married and they found and something odd and the. Decided to go to 1987 and they now having 2 kids you and your older brother named junyoung 7years old and you're 3years old

Yoon young:babies we're going to past stay at grandparents home okay

Haejun: don't fight and don't cry baby okay